---
name: collectible-authentication-guide
description: |
  Provides authentication criteria and provenance verification processes for collectible items including stamps, coins, trading cards, art, and memorabilia. Covers physical examination points, red flags for counterfeits, documentation verification, and professional authentication service options by collectible type.
  Use when the user asks about verifying the authenticity of a collectible, identifying counterfeits, checking provenance, or understanding authentication grading services.
  Do NOT use for determining the monetary value of collectibles (use collection-valuation-guide), cataloguing and inventory management (use collection-inventory-builder), forensic analysis or legal evidence examination, or authentication of fine art for museum or institutional purposes.
license: Apache-2.0
metadata:
  author: foundry-skills
  version: "1.0.0"
  tags: "research guide checklist analysis"
  category: "hobbies-crafts"
  subcategory: "collecting"
  depends: ""
  disclaimer: "none"
  difficulty: "intermediate"
---
# Collectible Authentication Guide

## When to Use

**Use this skill when:**
- A user wants to verify whether a specific collectible item is genuine before purchasing it at a flea market, online marketplace, estate sale, auction, or private sale
- A user holds an item in hand and wants to perform physical examination checks to rule out counterfeiting or reproduction
- A user received a collectible as a gift or inheritance and wants to understand whether it is authentic before insuring, displaying, or selling it
- A user wants to understand the provenance chain for a collectible -- who owned it, how it changed hands, and whether the documentation supporting that chain is credible
- A user is evaluating a Certificate of Authenticity (COA) or grading slab and wants to know whether the document or encapsulation itself is legitimate
- A user notices red flags with a listing -- a price that seems too low, a seller with many copies of a rare item, or inconsistencies in photographs -- and wants a systematic checklist to evaluate risk
- A user wants to understand which professional authentication or grading service is appropriate for their specific collectible type and how the submission process works

**Do NOT use when:**
- The user's primary question is what their item is worth in dollar terms -- use `collection-valuation-guide`, which handles market pricing, recent auction comps, and condition grading impact on value
- The user needs to catalogue, organize, or build an inventory of a collection -- use `collection-inventory-builder`
- The user requires forensic analysis that will be submitted as legal evidence in a fraud case, insurance dispute, or criminal prosecution -- this requires court-qualified expert witnesses, not an AI assistant
- The user is authenticating fine art (original paintings, sculptures) for museum acquisition, bequest valuation, or institutional deaccessioning -- these require in-person physical and scientific examination by credentialed conservators
- The user is asking about counterfeit currency or financial instruments -- this is a law enforcement matter under Title 18 U.S.C. § 471, not a hobby collecting question
- The user is asking whether a reproduction item they knowingly purchased is "as good as the real thing" -- this is a values question, not an authentication question
- The user needs authentication for import/export customs purposes -- this requires licensed appraisers and country-specific documentation standards

---

## Process

### Step 1: Identify the Item, Category, and Context

Gather the following information before beginning any authentication analysis. The collectible category determines every subsequent examination criterion.

- **Item type** -- coin, stamp, trading card, comic book, sports autograph, signed memorabilia (jersey, baseball, bat), vintage photograph, art print or lithograph, vinyl record, vintage watch, antique toy, or other. If "other," ask the user to describe what kind of object it is.
- **Specific description** -- for coins: country, year, denomination, mint mark, grade if known. For cards: brand (Topps, Fleer, Upper Deck, Bowman), year, set, card number, player or subject. For autographs: who signed, on what surface (photograph, baseball, jersey, document), in what ink medium. For stamps: country, Scott catalog number or year and denomination, used vs. unused.
- **Acquisition context** -- where and how is this item being obtained or considered? Options include: authorized dealer with verifiable storefront, major auction house with buyer guarantees, secondary online marketplace (eBay, COMC, Heritage Auctions), flea market or antique mall, estate sale, private seller known personally, and inheritance. Risk level differs significantly across these contexts.
- **Price relative to market** -- ask the user what they are being asked to pay and compare against known market references. A price more than 40% below recent comparable sales is the single most reliable fraud indicator across all collectible categories.
- **Documentation provided** -- has the seller provided a COA, a grading slab, auction house lot records, a receipt, dealer invoices, or any provenance documentation? Note every document and assess each independently.
- **Physical access** -- is the user holding the item, examining it in person at a venue, or reviewing it only from photographs in an online listing? Confidence in any assessment must be explicitly downgraded when the user cannot physically handle the item.
- **User experience level** -- does the user collect this category regularly, or is this their first encounter? A newer collector will need more guidance on what "correct" feels and looks like and should be steered more strongly toward professional authentication.

---

### Step 2: Assess Counterfeiting Risk for the Specific Item

Not all collectibles attract the same level of forgery activity. Risk is driven by two factors: how much money a convincing fake can net, and how easily the counterfeit can be produced.

**High risk (counterfeits are common and commercially produced):**
- Any coin worth over $300 in authentic condition, particularly key-date issues: 1909-S VDB Lincoln cent, 1916-D Mercury dime, 1879-CC Morgan dollar, 1804 Draped Bust dollar, pre-1933 U.S. gold coins. Chinese-made counterfeit coins of these issues are mass-produced and sold globally.
- Vintage trading cards with raw retail values over $200: 1952 Topps #311 Mickey Mantle, 1986-87 Fleer #57 Michael Jordan, 1989 Upper Deck #1 Ken Griffey Jr., 1916 Collins-McCarthy Babe Ruth, T206 Honus Wagner. Reprints and altered cards (re-colored, trimmed, or repressed corners) are pervasive.
- Autographed memorabilia, particularly sports autographs. The FBI estimates the sports memorabilia market has a counterfeit rate exceeding 50% by volume. Autographs of deceased signers (Mickey Mantle, Babe Ruth, Marilyn Monroe) are the highest risk because no living comparison is available.
- First editions of landmark literary works: first printings of Hemingway, Fitzgerald, Tolkien, early Harry Potter, and similar titles.
- Vintage comic books with certified values over $500: Action Comics #1, Detective Comics #27, Amazing Fantasy #15, etc.
- Pre-WWII stamps with catalog values over $200: 1918 U.S. 24-cent "Inverted Jenny," British Penny Black, pre-1870 U.S. issues.

**Moderate risk (counterfeiting exists but is less sophisticated):**
- Coins valued $50-300 in the specific grade being sold.
- Trading cards valued $50-200, particularly modern parallels and refractors where print-on-demand fakes have become common.
- Concert and event posters from legendary artists (Fillmore-era posters, KISS, The Beatles, etc.).
- Vintage advertising signs (Coca-Cola, gas station, tobacco).
- Signed books and documents where the signer is still living but signatures are worth $100 or more.

**Lower risk (counterfeiting is uncommon or commercially impractical):**
- Items worth under $50 retail -- the economics of counterfeiting rarely work at this price point.
- Common coins and stamps with abundant authentic supply.
- Modern collectibles with robust manufacturer security features (holographic inserts, serialized parallels, DNA-tagged memorabilia).
- Items with inherent age verification -- genuine patina and wear patterns on metal items are difficult and expensive to fake convincingly.

---

### Step 3: Guide Physical Examination by Collectible Category

Each category requires a different physical toolkit and examination methodology. The level of scrutiny must match the risk level established in Step 2.

**Recommended basic toolkit applicable across categories:**
- 10x jeweler's loupe (available for $10-20 at craft and jewelry supply stores) -- the single most useful tool for collectible authentication
- Precision digital scale accurate to 0.01 grams (available for $15-30) -- essential for coins and some stamps
- Digital calipers accurate to 0.01mm -- for coins, stamps, and edge measurement
- UV/black light flashlight (365nm wavelength preferred over cheaper 395nm) -- detects paper treatments, ink alterations, and modern fluorescent brighteners
- Perforation gauge (for stamps) -- a printed card or digital app that measures perforations per 2 centimeters
- Macro photography capability -- a smartphone with a macro lens attachment ($10-20) can substitute for a loupe for documentation purposes

---

**COINS:**

Weight and dimensions are the first line of defense. Every sovereign mint publishes exact specifications that counterfeits rarely replicate perfectly.

- Weigh the coin on a precision scale. A genuine 1 troy ounce American Silver Eagle weighs 31.10 grams; a genuine Morgan dollar weighs 26.73 grams; a genuine Lincoln cent weighs 2.50 grams (post-1982, zinc) or 3.11 grams (pre-1982, copper). Any deviation beyond ±0.1 grams warrants extreme suspicion.
- Measure diameter with calipers. A Morgan dollar should measure 38.1mm. A genuine Walking Liberty half dollar measures 30.6mm. Counterfeit dies rarely hit both weight AND diameter correctly.
- Reeding (edge milling): count the reeds on dollar coins (Morgan dollars have 189 reeds; Peace dollars have 150; Eisenhower dollars have 185). Counterfeit coins often have incorrect reed counts.
- The "ping test" for silver coins: hold the coin loosely between two fingers and tap it with another coin or a pen. Genuine silver coins produce a sustained high-pitched musical ring (approximately 1-3 seconds). Base metal counterfeits produce a short dull thud. This test is highly reliable and requires no equipment.
- Magnetic test: silver, gold, platinum, and copper are non-magnetic. Use a strong rare-earth (neodymium) magnet. If the coin sticks to the magnet, it is not what it claims to be. Note that some coins will "slide" slightly even without sticking due to eddy current effects -- this is normal for genuine precious metal coins and is actually an anti-counterfeiting indicator. Hold the magnet at an angle and let the coin slide down it; genuine silver coins will slide slowly due to eddy currents, while aluminum and zinc fakes will slide quickly.
- Die doubling and known die varieties: high-value coins have extensively catalogued die characteristics (the 1955 Doubled Die Lincoln cent, for example, shows extreme doubling on "LIBERTY" and the date). If a coin is claimed to be a known die variety, verify that the specific die characteristics match published references such as the Cherrypickers' Guide.
- Seam lines: cast counterfeits (made by pouring molten metal into a mold) show a faint seam line around the coin edge where the mold halves met. Examine the edge at 10x magnification.
- Artificial toning: genuine toning on silver coins develops over decades and shows rainbow iridescence at coin edges. Artificially toned coins (chemically treated to appear aged) often show toning concentrated unnaturally at the center of the coin, toning that appears too uniform, or a chemical smell.

---

**TRADING CARDS:**

The fundamental challenge with trading card authentication is that high-quality inkjet printing on appropriate paper can produce convincing fakes. Physical examination must be methodical.

- **Cardstock density and flex:** Hold the card between thumb and forefinger and gently flex it. Authentic cards from major manufacturers have a consistent spring-back. A 1986 Fleer card should flex and return like every other 1986 Fleer card in the set. If one card from the set feels different -- thinner, more rigid, or more floppy -- it is suspect.
- **Print rosette pattern:** This is the most reliable physical test. Under a 10x loupe, examine the image area of any authentic offset-printed card. You will see a regular pattern of colored dots arranged in rosettes (overlapping circles). Counterfeits printed on inkjet printers show a fine grid of tiny dots without the rosette pattern. Laser-printed counterfeits show solid toner deposits. This test works for cards from approximately 1950 through present.
- **Color registration:** Under magnification, examine where two colors meet (the edge of a player's skin against a jersey, for example). Authentic cards show clean color separation. Counterfeit printing often shows a slight halo or offset of 0.1-0.3mm between color layers.
- **Paper fluorescence under UV light:** Pre-1970s cardstock (and many authentic vintage cards through the 1980s) does not fluoresce brightly under UV light because it lacks optical brightening agents (OBAs). Modern printing paper almost universally contains OBAs and glows bright white-blue under 365nm UV light. If a card claimed to be from 1952, 1962, or 1986 glows brightly under UV, it was printed on modern paper.
- **Card back examination:** Counterfeiters frequently put more effort into the card front than the back. Examine the back under magnification for text sharpness, color registration, and print quality. Compare back border alignment with known authentic examples.
- **Trimming detection:** A common form of card fraud is trimming (cutting a lower-grade card's edges to make it appear sharper and artificially upgrade its grade). Measure the card dimensions. A standard modern card should measure 2.5 inches × 3.5 inches (63.5mm × 88.9mm). Pre-war cards vary by issue but have published dimensions. Any card measuring more than 0.5mm shorter than the published standard on any edge has likely been trimmed. Grading services use precision measuring devices for exactly this purpose.
- **Artificial corner rounding/pressing:** Some fraud involves pressing creases or artificially rounding corners to simulate wear on a fake vintage card, or conversely, pressing wrinkles out of genuine cards to upgrade apparent condition. Pressed cards often show micro-cracking of the surface coating under 10x magnification.

---

**AUTOGRAPHS AND SIGNED MEMORABILIA:**

Autograph authentication is the most subjective area of collectibles authentication. No single feature is definitive; authentication requires a cumulative assessment of multiple factors.

- **Reference comparison:** Gather 3-5 documented authentic signatures from the same person from the same approximate time period. Signatures change significantly over decades -- a 1950s Mickey Mantle signature looks quite different from his 1980s signature, both in form and in the hand tremor visible in his later years due to health issues. Use auction house records, established PSA/JSA population reports, and recognized reference books.
- **Pen pressure mapping:** Authentic signatures show natural variation in pen pressure -- heavier where the pen begins or changes direction, lighter in rapid strokes. Examine the ink depth under magnification. Traced forgeries show artificially uniform pressure throughout. Freely signed authentic signatures often show slight pen-lift points and pressure transitions.
- **Stroke speed indicators:** Rapid, confident signatures leave thinner ink trails in fast strokes and slightly wider deposits where the pen slows at direction changes. Slowly drawn forgeries show ink pooling throughout the signature because the forger is maintaining slow, controlled movement to copy the shape.
- **Ink era consistency:** Ballpoint pens were not commercially available until 1945 and not widely used until the late 1940s-1950s. A signature claimed to be from before WWII but written in ballpoint ink is impossible. Sharpie markers became common in the late 1960s. Match the ink medium to the historical period and to what is known about a specific signer's preferred medium.
- **Surface interaction:** Authentic ink signatures on photographs show ink that sits on top of the photo surface with natural interaction at the edges of each stroke. On cloth (jerseys, balls), authentic ink soaks into the fibers slightly at the edges of strokes -- "ink bleed." Printed or stamped signatures lack this fiber interaction.
- **Autopens and secretarial signatures:** High-volume signers (U.S. Presidents, major sports stars during peak fame) used autopen machines (consistent machine-produced signatures with zero pressure variation) or secretarial signing (a staff member signing on their behalf). These are not technically forgeries but are misrepresented if sold as authentic personal signatures. Autopen signatures show perfectly consistent pen pressure throughout because a machine maintains constant force.
- **Known signing habits:** Many signers sign consistently in the same location (Babe Ruth typically signed across the sweet spot of baseballs; Michael Jordan typically signed across the number on jerseys). Deviation from known habits is a soft red flag. Established authentication services catalog these habits.

---

**STAMPS:**

Philatelic authentication involves precise measurement and material science that rewards meticulous attention to published catalog specifications.

- **Perforation gauge measurement:** Count the number of perforation holes per 2 centimeters using a printed or digital perforation gauge. The Scott Specialized Catalogue of United States Stamps publishes exact perforation measurements for every U.S. stamp issue. A stamp perforated 11 should measure exactly 11 holes per 2 centimeters. Reprints often have incorrect perf gauges.
- **Watermark detection:** Many stamps use watermarked paper as a security feature. Place the stamp face-down in a watermark tray with a few drops of watermark fluid (or lighter fluid in a well-ventilated area) and a black background. The watermark -- a pattern pressed into the paper during manufacture -- will become visible. Match the watermark design to the published specification for that issue. Many fakes omit or incorrectly replicate the watermark.
- **Gum examination:** Original gum (OG) on mint stamps from before 1960 should show age-appropriate characteristics: slight yellowing, possible hinging or hinge remnants from album mounting, and a dull or semi-gloss appearance. Re-gummed stamps (stamps from which original gum was removed and new gum applied) appear artificially bright, too uniform, and often fluoresce differently under UV light because modern adhesives contain different chemicals than period gum. The re-gumming fraud can add 50-300% to a stamp's value by converting a "no gum" stamp into an "original gum" example.
- **Printing method identification:** U.S. stamps from different eras use different printing methods: intaglio/recess printing (engraved) produces ink that stands slightly above the paper surface and can be felt by running a fingernail across it; flat plate printing is smooth; photogravure shows a fine halftone dot pattern under magnification; offset lithography shows rosette dot patterns. Match the printing method to the documented production method for the specific stamp issue.
- **Paper type and color under UV:** Different paper types used in different eras fluoresce differently. Pre-1934 U.S. stamps use paper that glows a certain way; modern reprints often glow much more brightly. The specific fluorescence characteristics for key issues are documented in philatelic literature and can distinguish genuine stamps from reprints and forgeries.
- **Expertizing services:** For stamps with catalog values over $100, submit to the American Philatelic Expertizing Service (APEX) or the Philatelic Foundation in New York. These services use spectrographic analysis, UV examination, and expert panel review to issue opinions on genuineness.

---

**ART PRINTS AND LITHOGRAPHS:**

- **Plate mark examination:** Intaglio prints (etchings, engravings, aquatints) are printed by pressing damp paper against a metal plate under high pressure, leaving a distinct embossed impression -- the plate mark -- around the image area. This mark can be felt by running a fingernail across the margin of the print. Photographic reproductions of intaglio prints look correct under normal viewing but lack this plate mark entirely.
- **Stone/plate texture for lithographs:** Original hand-pulled lithographs from a stone or aluminum plate show subtle texture from the printing surface when viewed under raking light (a light source held at a very low angle to the paper surface). Commercial offset reproductions show a flat, consistent surface.
- **Edition markings verification:** Legitimate limited edition prints are numbered in pencil in the lower left margin (e.g., "47/250") and signed in pencil in the lower right margin. The use of pencil is intentional -- it cannot be photographically reproduced on a printed copy, confirming it was applied by hand. Printed signatures (signatures that are part of the printed image rather than applied by hand) reduce authentication value significantly.
- **Paper aging and foxing:** Genuine vintage prints show foxing (brown spots from mold and oxidation), yellowing, and paper brittleness consistent with their claimed age. A print claimed to be from 1920 with perfectly white, supple paper is suspect. However, conserved prints may have been deacidified and restored, so perfect paper alone is not disqualifying.
- **Publisher's chop marks and blind stamps:** Many print publishers, print studios, and estates use an embossed blind stamp or red/black chop mark in the margin to authenticate works from their inventory. Verify that the chop mark matches the publisher's known mark and that the publisher existed during the claimed period of production.

---

### Step 4: Evaluate All Documentation

Documentation assessment follows physical examination because documentation should confirm physical evidence, not substitute for it.

**Certificate of Authenticity (COA) quality assessment:**
- A credible COA identifies the specific item with enough detail that it cannot be transferred to a different item: description of the item, specific measurements or identifiers, condition notes, and a photograph of the specific item.
- The COA must identify the issuing authority with verifiable credentials. A COA issued by a named individual should list their qualifications. A COA from a recognized grading service references a verifiable certification number.
- The date of the COA should be logical relative to the item's history. A COA issued before the claimed acquisition date of the item is suspicious.
- A COA issued by the seller themselves has virtually no authentication value. It is equivalent to the seller verbally saying "it's real." Third-party authentication is the only meaningful form.
- Multiple COAs for the same item from different services may indicate that the item failed authentication at one service and the seller shopped for a more favorable opinion.

**Recognized third-party authentication and grading services by category:**
- Coins: PCGS (Professional Coin Grading Service) and NGC (Numismatic Guaranty Corporation) are the two dominant services. ANACS and ICG are recognized secondary services. Coins in PCGS or NGC slabs are considered authenticated and graded. Verify slab genuineness at the respective service's online verification tool by entering the certification number.
- Trading cards: PSA (Professional Sports Authenticator), BGS/Beckett Grading Services, and SGC (Sportscard Guaranty Corporation) are the three primary recognized services. PSA holds the largest population report database.
- Comics: CGC (Certified Guaranty Company) is the dominant service for comic authentication and grading.
- Autographs and memorabilia: PSA/DNA and JSA (James Spence Authentication) are the two most widely recognized services. LOA (Letter of Authenticity) from either carries significant market value.
- Stamps: APEX (American Philatelic Expertizing Service) and The Philatelic Foundation for U.S. stamps; BPA Expertising for British stamps; various national expertizing committees for other countries.
- Vintage watches: Rolex Service Centre, Omega Museum, and independent horological experts certified through the British Horological Institute (BHI) or American Watchmakers-Clockmakers Institute (AWCI).

**Provenance chain evaluation:**
- A provenance chain is a documented sequence of ownership from creation/origin to the present. Each link should be verifiable: dealer invoices, auction house records, estate documentation, insurance records, or published exhibition history.
- Gaps in provenance are common and not automatically disqualifying. A coin stored in a family collection for 60 years will have no paper trail for that period. The key is whether the physical examination matches the claimed age and origin.
- For pre-WWII items with European origins, provenance gaps covering 1933-1950 are extremely common due to wartime displacement. This specific gap pattern is well understood in the art and antiques trade and is not itself suspicious, though post-war restitution claims remain an issue for certain categories.
- Auction house records from recognized houses (Heritage Auctions, Sotheby's, Christie's, Stack's Bowers for coins, Robert Edward Auctions for sports) are the strongest single form of provenance documentation because auction houses conduct their own authentication before accepting consignments.

---

### Step 5: Assess Whether Professional Authentication Is Required

Not every item requires professional authentication. The following criteria determine when to recommend it.

**Always recommend professional authentication when:**
- The item is potentially worth over $200 and the user is making a purchase decision based on authenticity
- The user intends to resell the item -- items with professional authentication certificates sell for materially more and provide legal protection against future fraud claims
- The user intends to insure the item -- most collectibles insurance requires graded or expert-authenticated values
- The user is a relative newcomer to the specific collectible category and lacks the experience to evaluate physical examination findings reliably
- Physical examination reveals some criteria matching and some not matching, producing genuine uncertainty
- The item is an autograph by a deceased signer (the highest-risk category; physical examination alone is insufficient)

**Professional authentication is likely unnecessary when:**
- The item is worth under $50 and is not part of a larger suspicious lot
- The item is already in a PCGS, NGC, PSA, BGS, CGC, or JSA holder with a verifiable certification number
- The physical examination is unambiguously positive AND the acquisition context is low-risk (authorized dealer with return policy)

**Selecting a service:**
- Match the service to the category -- sending a coin to PSA or a trading card to NGC is non-standard and produces less recognized results
- Understand the tier structure: most major services offer tiers based on item value and desired turnaround time. Express service for a $100 card costs more than the card is worth in grading fees -- choose tiers appropriate to the item's potential value.
- For PCGS and NGC, standard tier costs approximately $30-50 per coin with 30-45 day turnaround. Express service is $75-150 with 15 business day turnaround. For PSA cards, standard service starts at approximately $25-50 per card with variable turnaround.
- Grading encapsulation also protects the item physically and establishes a condition record, which matters for value.

---

### Step 6: Synthesize and Deliver the Authentication Conclusion

After gathering physical examination results, documentation assessment, and risk context, synthesize into a structured verdict.

**Verdict categories and their criteria:**

- **Authentic (high confidence):** All physical examination criteria match published specifications. Documentation is credible and independently verifiable. Acquisition context is low-risk. No red flags identified. A conclusion of "Authentic (high confidence)" for an item worth under $100 in a low-risk context is reasonable. For items over $200, recommend professional authentication to confirm even a high-confidence positive finding, because the cost of authentication is justified by the item's value.
- **Likely authentic (moderate confidence):** The majority of physical examination criteria match. One or two criteria are inconclusive or untestable (for example, the user cannot perform the UV test). Documentation is present but not independently verified. Risk level is moderate. Recommend professional authentication before any purchase over $100.
- **Uncertain:** Physical examination produces mixed results -- some criteria clearly match, others clearly do not, or the user cannot perform sufficient tests. Documentation is absent or unverifiable. Risk level is high. Advise against purchasing without professional authentication or a fully documented return policy.
- **Likely not authentic:** Multiple red flags identified (3 or more). Physical examination reveals clear inconsistencies with known authentic examples for that specific issue. Documentation is absent, generic, or from the seller only. For this verdict, recommend declining the purchase and, if already purchased, pursuing return options.
- **Not authentic:** Physical examination definitively identifies the item as a counterfeit, reproduction, or intentionally misrepresented item. Examples: coin fails the magnetic test and the weight test; card fluoresces brightly under UV and lacks rosette print pattern; autograph shows machine-printed characteristics. This verdict requires unambiguous evidence -- do not issue this verdict based on a single failed test.

For all verdicts, state explicitly what additional information or testing would change the assessment.

---

## Output Format

```
## Authentication Assessment

### Item Information
| Parameter            | Value                                        |
|----------------------|----------------------------------------------|
| Item type            | [Coin / Card / Autograph / Stamp / Print / Other] |
| Specific description | [Year, set, number, player, artist, etc.]    |
| Claimed date/era     | [Specific year or date range]                |
| Acquisition source   | [Flea market / Dealer / Online / Estate / etc.] |
| Asking price         | [$XX if pre-purchase / Paid $XX if owned]    |
| Market context       | [What authentic examples sell for in this condition] |
| Risk level           | [High / Moderate / Lower -- with brief justification] |
| Physical access      | [Item in hand / Photographs only / Not yet examined] |

---

### Physical Examination Checklist
*Items marked [CRITICAL] are most diagnostic for this collectible type.*

| Criterion            | Specification for Authentic Example | Observed Result | Match? | Notes |
|----------------------|--------------------------------------|-----------------|--------|-------|
| [Criterion 1]        | [Exact expected value or characteristic] | [What the user found] | ✓ / ✗ / ? | [Explanation if needed] |
| [Criterion 2]        | [Exact expected value or characteristic] | [What the user found] | ✓ / ✗ / ? | [Explanation if needed] |
| [Criterion 3 CRITICAL]| [Exact expected value or characteristic] | [What the user found] | ✓ / ✗ / ? | [Explanation if needed] |

*Legend: ✓ = Matches / ✗ = Does not match / ? = Could not test or inconclusive*

---

### Red Flags Identified
| Red Flag                | Present? | Severity  | Notes                          |
|-------------------------|----------|-----------|--------------------------------|
| [Red flag description]  | Yes / No | High / Med / Low | [Contextual explanation] |
| [Red flag description]  | Yes / No | High / Med / Low | [Contextual explanation] |

**Red flag count:** [X of Y checked are present]
**Cumulative risk:** [Low / Elevated / High -- note that 3+ red flags together strongly indicate inauthenticity]

---

### Documentation Evaluation
| Document              | Status               | Quality Assessment                |
|-----------------------|----------------------|-----------------------------------|
| COA (if present)      | Present / Absent     | [Third-party / Seller-issued / Recognized service] |
| Grading slab          | Present / Absent     | [Service name, cert number, verified Y/N] |
| Provenance chain      | Complete / Partial / Absent | [Gaps noted, strongest links identified] |
| Seller receipt        | Present / Absent     | [Seller contact info included Y/N] |
| Auction records       | Present / Absent     | [House name, lot number if applicable] |

---

### Physical Examination Tools Used / Recommended
| Tool                  | Used? | If Not Used -- Impact on Confidence    |
|-----------------------|-------|----------------------------------------|
| 10x loupe             | Y / N | Cannot assess print quality or fine detail |
| Precision scale       | Y / N | Cannot verify weight (critical for coins) |
| Digital calipers      | Y / N | Cannot verify dimensions               |
| UV flashlight (365nm) | Y / N | Cannot assess paper fluorescence or ink authenticity |
| Perforation gauge     | Y / N | Cannot verify stamp perf spec (stamps only) |
| Reference examples    | Y / N | Cannot compare to known authentic specimens |

---

### Verdict

**Authentication Assessment:** [Authentic / Likely authentic / Uncertain / Likely not authentic / Not authentic]
**Confidence Level:** [High / Moderate / Low]
**Key Determining Factors:** [2-3 bullet points naming the most diagnostic evidence]

**Recommendation:**
- [ ] Proceed with purchase -- physical and documentary evidence is satisfactory
- [ ] Proceed only after professional authentication -- item value justifies the cost
- [ ] Request additional testing or photographs before deciding
- [ ] Decline purchase -- multiple red flags indicate unacceptable risk
- [ ] Pursue return/refund -- if already purchased and evidence suggests inauthenticity

**What would change this assessment:** [Specific tests or evidence that would upgrade or downgrade the verdict]

---

### Professional Authentication Recommendation (if applicable)

| Service               | Category       | Estimated Cost       | Typical Turnaround     |
|-----------------------|----------------|----------------------|------------------------|
| [Service name]        | [Coin/Card/etc.] | $[range] per item  | [Weeks]                |
| [Service name -- express] | [Same]    | $[range] per item    | [Faster turnaround]    |

**Submission notes:** [Any category-specific instructions -- e.g., remove from existing holder, specific packaging requirements, recommended tier based on item value]
```

---

## Rules

1. **Never declare an item definitively authentic based on photographs alone.** State this limitation explicitly every time a user is evaluating an item they cannot physically examine. Photographs can be manipulated, and the most diagnostic physical tests -- weight, dimensional measurement, texture, UV response, the ping test -- are impossible from images. Reduce confidence rating by at least one level when physical access is unavailable.

2. **Price anomaly is the most powerful red flag across all categories.** Any item offered at more than 40% below recent comparable sales warrants immediate heightened scrutiny. A $50 price for a card that sells for $300 in lower grades is not a bargain -- it is a warning. Apply this check before any physical examination and let it calibrate the user's risk awareness.

3. **Always recommend professional authentication for any item potentially worth over $200.** The cost of authentication ($25-100 for most items) is trivially small relative to the purchase price and the financial and emotional cost of being deceived. Frame this as not just fraud prevention but value confirmation and resale documentation.

4. **COAs from sellers carry virtually no authentication weight.** Any seller can print a COA. Always ask who issued the COA and whether the issuing party is a verifiable, independent third party with a dispute resolution mechanism. A seller-issued COA should be noted in the documentation assessment but should not improve the confidence rating.

5. **Red flags are cumulative, not standalone.** A single red flag may have an innocent explanation. Three or more red flags together make a coherent pattern. When multiple red flags co-occur -- low price, absent documentation, high-volume seller, item in unusually perfect condition -- state that the cumulative pattern significantly increases fraud probability even if no single indicator is definitive.

6. **Autograph authentication is a specialist discipline.** Without direct comparison to multiple documented authentic examples from the same time period, autograph assessment is highly unreliable. Physical examination guidelines above help eliminate obvious forgeries and autopens, but positive autograph authentication for items worth over $200 requires a recognized service (PSA/DNA or JSA). Never provide a confident positive verdict for high-value autographs without professional review.

7. **Grading slabs can themselves be counterfeited.** PCGS, NGC, and PSA slabs have been counterfeited with genuine coins or cards replaced with fakes inside the holder. For any slabbed item, verify the certification number directly on the grading service's official verification website before accepting the slab as authentication evidence. A certification number that returns no record, or that describes a different item, means the slab is counterfeit.

8. **Assess the specific item, not the category.** "1986 Fleer Basketball" is not sufficient. The item is a specific card -- 1986 Fleer #57 Michael Jordan -- and authentication criteria must be tied to that specific issue, that specific manufacturer's production specifications for that specific year and set. Generic category-level advice is insufficient and reduces the quality of the assessment.

9. **The acquisition context and seller behavior are authentication evidence.** A seller who refuses to allow close inspection, declines to provide a receipt, has many copies of the same allegedly rare item, or pressures the buyer to decide quickly is exhibiting behavioral red flags that belong in the assessment. Legitimate sellers of authentic items expect and welcome scrutiny.

10. **Do not provide authentication assessments as legal testimony, insurance documentation, or expert witness opinions.** This is educational guidance for personal collecting decisions. If a user needs official authentication for an insurance claim, estate settlement, legal proceeding, or sale contract above a threshold amount, they require a human expert who can take legal responsibility for their opinion. State this clearly when the use case approaches legal or financial formality.

---

## Edge Cases

**User is evaluating an item from an online listing with no physical access:**
Explicitly downgrade confidence for every test that requires physical handling. Focus the assessment on what photographs can reveal: whether the proportions look correct relative to the claimed issue, whether any obvious printing artifacts are visible, whether the seller is using actual photographs of the item versus stock images (a major red flag in itself), and whether edge details, back printing, or slab information are visible. Recommend requesting specific photographs: the item's back, its edge, a scale or ruler for reference, and a UV photograph. For any item over $100, recommend purchasing only from sellers who offer a return window contingent on professional authentication, or purchasing from a marketplace that provides buyer guarantees with authentication disputes. Major auction platforms with buyer protection programs provide meaningful recourse; anonymous social media sales do not.

**User has an item that was authenticated by a now-defunct or disreputable service:**
Several historical authentication services are no longer recognized by the collector community due to standards failures, fraud, or business closure. If the user presents a COA from a service that is not currently recognized (check against the PCGS/NGC/PSA/CGC/JSA active status and community recognition), treat the documentation as having minimal evidentiary weight. Focus entirely on physical examination criteria and recommend resubmission to a currently recognized service. Also note that authentication service slabs from the early 1990s used anti-tampering measures less sophisticated than current holders -- these vintage slabs can sometimes be opened and reclosed without obvious damage.

**User already purchased the item and now suspects it is not authentic:**
The approach shifts from pre-purchase evaluation to post-purchase documentation. First, instruct the user to document the item's current condition extensively with photographs under multiple lighting conditions, including UV. Document all red flags systematically. Second, seek professional authentication immediately -- without a professional opinion, the seller has no obligation to accept a return. Third, review the purchase terms: dealer/shop purchases typically have return policies; most reputable auction houses offer authenticity guarantees; online marketplaces have buyer protection programs with specific windows (typically 30-180 days depending on platform). Fourth, for items purchased from private sellers, understand that recourse is limited without professional authentication confirming inauthenticity and documented evidence of misrepresentation. Keep all communication with the seller in writing. Fifth, if the item was purchased for over $1,000 and professional authentication confirms it is counterfeit, consult with the platform or a local consumer protection authority about options, as intentional fraud of this magnitude may have legal remedies.

**User inherited a collection of unknown items with no documentation:**
This is a documentation-absent scenario, not necessarily an inauthenticity scenario. Many genuine collectibles have been stored in family collections for decades with no paperwork. Approach this systematically: sort items visually by likely value category first. Identify any items that appear to be in the high-risk, high-value category and prioritize those for detailed physical examination. For coins, a basic numismatic reference (Red Book for U.S. coins, for example) allows immediate identification and rough value assessment that determines authentication priority. For stamps, a basic Scott catalog identification. Do not assume inherited items are inauthentic -- inherited items often have genuine provenance precisely because they were not purchased from a suspicious source. Build documentation going forward: record the inheritance source, date, and any family history about the items. Photographs and a written description now become the beginning of a new provenance record.

**User is evaluating a bulk lot (multiple items purchased together):**
The economics of counterfeiting create a predictable pattern: forgers rarely bother with low-value common items in a lot but do include high-value "anchor items" to justify the price of the lot. For any bulk purchase, identify the 2-5 highest-value items in the lot and authenticate those first. If the anchor items pass authentication, the remainder of the lot becomes substantially more credible because it suggests a single genuine source. If any anchor item fails, treat the entire lot as compromised -- a seller willing to include fake high-value items in a lot is likely also padding lower-value items. Never let a seller use the existence of genuine items in a lot as implicit authentication for the entire lot without individual examination.

**User is dealing with a recently counterfeited modern item:**
Modern counterfeiting has expanded into collectible categories previously considered lower-risk: modern Pokémon and sports card parallels, modern limited-edition sneakers, and modern watch accessories. The UV paper test is less reliable for modern fakes because counterfeiters now use paper stocks with similar OBA content. For modern cards specifically, weight measurement has become increasingly important -- PSA and BGS use precision scales as part of their grading process because some modern counterfeiters produce cards with correct visual characteristics but incorrect paper density. Modern card authentication also relies heavily on print rosette pattern examination because even high-quality inkjet printing at 1200 DPI does not replicate the rosette pattern of commercial offset presses. Recommend community-specific resources -- for modern Pokémon cards, established authentication communities maintain extensive counterfeit databases with specific known fake editions.

**User encounters a legitimate reproduction that is being misrepresented:**
Some reproductions are legal and legitimate: commemorative coin reprints, licensed card reprints, and authorized facsimile autographs are all commercially produced with honest intent. These become fraud only when they are misrepresented as originals. A 1952 Topps reprint card is produced with correct retro printing but on modern paper stock that will immediately fail the UV test and likely fail the rosette test. An "autograph" produced through a licensed facsimile program (where a signer authorizes mass-production of their signature on merchandise) typically says "facsimile" or "autographed copy" on the item itself -- if this notation has been obscured or removed, that is deliberate misrepresentation. Coins produced as "copy" items (legally required to be stamped "COPY" under the Hobby Protection Act of 1973 in the U.S.) are authentic reproductions but fraudulent if the COPY mark is removed or obscured. Check for surface alteration at the location where a COPY mark would be stamped (typically the reverse).

---

## Example

**Input:** "I'm looking at buying a 1909-S VDB Lincoln cent at a coin show. The dealer is asking $1,200 for it in what he says is Fine-12 condition. He says it's genuine but it's unslabbed. I have a scale and calipers with me. What should I check and how do I know if it's real?"

**Output:**

## Authentication Assessment

### Item Information
| Parameter            | Value                                                  |
|----------------------|--------------------------------------------------------|
| Item type            | Coin (U.S. cent)                                       |
| Specific description | 1909-S VDB Lincoln Wheat Cent, claimed Fine-12 grade  |
| Claimed date/era     | 1909, San Francisco Mint (S mintmark)                 |
| Acquisition source   | Coin show dealer (unslabbed, raw coin)                |
| Asking price         | $1,200                                                 |
| Market context       | Authentic 1909-S VDB in F-12 typically sells $700-$1,100 in current market; VF-20 examples reach $1,400-$1,800. The asking price is at the high end for the claimed grade but not implausible for a coin show premium. |
| Risk level           | **HIGH** -- The 1909-S VDB is the most counterfeited Lincoln cent in existence. Chinese-made counterfeits at this specific date/mintmark combination are mass-produced and widely circulated. Genuine examples are worth serious money; convincing fakes are worth nothing. |
| Physical access      | Item in hand -- proceed with full examination          |

---

### Physical Examination Checklist

*Items marked [CRITICAL] are most diagnostic for this specific coin.*

| Criterion               | Specification for Authentic 1909-S VDB | What to Check / Observe | Match? | Notes |
|-------------------------|----------------------------------------|--------------------------|--------|-------|
| Weight [CRITICAL]       | 3.11 grams (±0.05g tolerance for circulation wear on an F-12 example) | Weigh immediately on your precision scale | ? | Deviation of more than 0.1g is disqualifying. Common Chinese counterfeits come in at 3.0g or 3.2g. |
| Diameter [CRITICAL]     | 19.05mm exactly | Measure with calipers | ? | Counterfeits often run 18.9mm or 19.2mm. |
| "VDB" designer initials | Must appear on the reverse at the bottom center, between the wheat stalks. Letters should be sharp with clear serifs. | Examine under 10x loupe. "V", "D", and "B" should have crisp, individually cut letter forms | ? | The "D" in "VDB" is a common point of weakness on cast counterfeits -- it appears mushy. |
| "S" mintmark [CRITICAL] | Located on the obverse below the date. The "S" should have a specific knob shape with slightly open top and bottom loops characteristic of the San Francisco Mint's 1909 punch. | Examine mintmark under 10x loupe. Compare S-punch shape to a reference image of the 1909-S. | ? | The most common fraud is an altered 1909 Philadelphia cent with an "S" added. Look for tool marks, roughness, or a slightly different metal color/texture around the mintmark. Any roughness around the S is disqualifying. |
| Coin edge              | Plain edge (no reeding) -- the 1909 Lincoln cent has a smooth plain edge | Run your fingernail around the entire edge. It should be completely smooth and show only wear patterns, not reeding or seam lines. | ? | Cast counterfeits show a seam line where the mold halves met. |
| Die strike characteristics | High-relief facial details on Lincoln: the bow tie, jacket lapels, and hair above the ear should show appropriate wear for F-12 -- high points worn flat, but moderate detail remaining. | Under 10x loupe, examine Lincoln's cheekbone, jaw line, and the wheat stalk tips (which wear first in genuine circulation) | ? | Counterfeits from cast dies often show mushy, "soft" details throughout rather than a wear pattern concentrated on high points. Genuine wear is smooth and directional; cast fakes show uniform soft detail everywhere. |
| Metal composition       | 95% copper, 5% tin and zinc. Non-magnetic. Should not be attracted to a magnet. | Hold a neodymium magnet near the coin. It should not attract or stick. Then hold the coin at an angle above the magnet and let it slide -- genuine copper coins will slide freely without resistance. | ? | If the coin sticks to the magnet or shows strong magnetic attraction: it is not a genuine 1909-S VDB. |
| Color and surface luster | An F-12 circulated cent should have a medium brown color with even wear. It should NOT look bright copper-red (that would be Uncirculated, inconsistent with F-12 claim). No artificial luster. | Check whether the color is consistent with 115+ years of circulation. Artificial toning can be detected by an unusual smell (sulfur, chemicals) or by toning that appears concentrated in recessed areas rather than distributed naturally. | ? | A cent that looks unnaturally dark (artificially toned to hide bright metal of a new counterfeit) is suspect. |
| Date numerals          | The "1909" date should have numerals with specific serif shapes for the 1909 Lincoln cent master die. The "9" digits have a specific tail shape. | Under 10x loupe, examine the date numerals closely. The numeral shapes should match published examples from 1909-S VDB reference photography. | ? | Added or altered date numerals (from a 1909 plain cent or a different date) show tooling marks, inconsistent metal flow, or slightly different numeral shapes. |

---

### Red Flags to Check

| Red Flag                                      | Present? | Severity | Notes                                                        |
|-----------------------------------------------|----------|----------|--------------------------------------------------------------|
| Asking price more than 40% below market       | No       | --       | $1,200 is within plausible range for F-12; not a price red flag |
| Coin is unslabbed for a $1,200 example        | Moderate | Med      | A genuine 1909-S VDB in this price range is almost always slabbed. Legitimate reason possible (dealer preference for raw) but worth noting. |
| Seller discourages examination or measurement | ?        | High     | You have the right to examine any coin you are considering buying. Refusal or impatience is a significant red flag. |
| Mintmark shows any roughness or tool marks    | ?        | High     | The most common alteration for this coin is adding an S mintmark |
| Weight deviates more than 0.1g from 3.11g    | ?        | High     | A wrong weight is near-conclusive evidence of inauthenticity |
| Mushy detail throughout (not consistent with wear pattern) | ?  | High  | Genuine wear concentrates on high points; cast fakes show uniform softness |

**Red flag count:** [Complete after examination]
**Cumulative risk:** HIGH -- regardless of how the coin looks to the naked eye, this specific date/mintmark is the most counterfeited Lincoln cent issue in existence.

---

### Documentation Evaluation

| Document          | Status   | Quality Assessment                                         |
|-------------------|----------|------------------------------------------------------------|
| COA               | Absent   | No COA provided. For an unslabbed coin this is standard.   |
| Grading slab      | Absent   | Coin is raw (unslabbed). This is the primary documentation gap for a $1,200 coin. |
| Provenance chain  | Unknown  | Ask the dealer where this coin came from (previous owner, auction source). Document the answer. |
| Dealer receipt    | Unknown  | Request a written receipt with full description, grade claim, price, and dealer's name/contact. Any legitimate coin show dealer will provide this. |

---

### Physical Examination Tools Used

| Tool              | Available | If Not Used -- Impact                                         |
|-------------------|-----------|---------------------------------------------------------------|
| Precision scale   | Yes       | Use it first. Weight is the fastest definitive test.         |
| Digital calipers  | Yes       | Use after weight. Diameter confirmation adds confidence.      |
| 10x loupe         | Recommended | Mintmark examination is critical and requires magnification. If
