How to Tell if a Shipwreck Coin Is Real

A shipwreck coin is authenticated by three things: a documented salvage source, third-party certification, and metal and design consistent with the type. Here is how to check each.

A shipwreck coin is authenticated by three things: a documented salvage source, third-party certification, and metal, weight and design consistent with the type it claims to be — check each in that order and almost every problem coin falls out. The single most common failure is not a fake coin at all: it is a genuine colonial coin wearing a wreck story nobody can document.

What does “authentic” actually mean for a wreck coin?

Two separate claims are being made when someone sells you a shipwreck coin, and they fail independently. The first is that the coin is a genuine period issue — struck at a Spanish colonial mint, in the right metal, to the right standard. The second is that this particular coin came off a particular wreck. Most sellers use the same word, “authentic,” for both.

Almost all of the market's honest trouble sits in the second claim. Genuine cobs are common; documented wreck cobs are not. That gap is exactly where value is manufactured, because a wreck name multiplies price. In our own August 2026 eBay study, a raw El Cazador 2 reales cleared a $75 median while the same coin in a slab with the wreck named on the label cleared $200 — a 2.7x spread created by paper, not metal.

Treat the coin and the story as two separate audits. A coin can be genuine and its provenance still be unsupportable.

Step 1 — Is there a documented salvage source?

Authentic wreck coins come from a short, closed list of legally salvaged sites. That list is historical fact, not marketing: the 1622 Atocha and Santa Margarita, the 1641 Concepción, the 1654 Capitana at Chanduy, the 1656 Maravillas, the 1715 Plate Fleet, the 1733 Keys fleet, El Cazador, and a handful of others. If a wreck name is not on the list of sites that were actually worked and sold from, the coin's story is unsupported by default.

Certain names should stop a sale outright. No coins exist from the 1628 Matanzas Bay capture — that silver was taken intact by Piet Heyn and reminted in the Netherlands. The 1708 San José is a protected site under litigation with no legal market. Padre Island 1554 material is state-held in Texas. Coins offered under those names are stories, not provenance.

Step 2 — Is it certified, and by whom?

NGC and PCGS are the two graders whose opinions the market actually pays for. For wreck material NGC's holders frequently read “Genuine” with a Shipwreck Effect designation and, where documentation supports it, the wreck named on the label. That label is not a grade in the numeric sense; it is an authentication plus a surface description.

Certification does two useful things. It removes the counterfeit question, and it moves the provenance claim from the seller's word onto a third party's label. It does not make a corroded coin a nice coin, and it does not prove the wreck attribution if the label omits the wreck name.

Verify the certificate number on the grader's own site. A holder with no matching record online — or a label whose photos do not match the coin in hand — is the end of the conversation.

A slab that does not name the wreck is authenticating the coin, not the story. Read the label literally.

Step 3 — Do metal, weight and design match the type?

Spanish colonial silver was struck to a published standard, and that standard is the cheapest test you can run. A hammered 8 reales of the cob era weighs about 27.47 g at .9305 fine; the later milled 8 reales runs about 27.06 g. Fractions scale down from there — 4 reales at roughly half, 2 reales at a quarter.

Weigh the coin on a scale that reads to 0.01 g. A cob that is 10% light is either clipped, badly corroded, or not silver. A cob that is heavy for its denomination is a red flag for a cast copy in the wrong alloy. Specific-gravity testing settles the metal question without damaging the coin.

Then look at how the coin was made. Genuine cobs were hand-struck on irregular, hand-cut flans: sharp, sometimes brutal, edges; off-centre strikes; doubled or partly missing legends; no seam. Cast fakes show soft detail, rounded rims, a granular field under magnification, and sometimes a faint line where two mould halves met. Transfer-die copies reproduce the host coin's scratches and dings — identical “damage” on two coins of the same type is a copied master, not a coincidence.

What do genuine sea-salvaged surfaces look like?

Long immersion leaves a signature that is hard to fake convincingly. Expect etched, slightly frosted fields; crystalline or granular patches where sulphides formed; high points worn soft while protected recesses keep detail; sometimes a faint encrustation in the legends. Coins from deep, cold, quiet water — El Cazador is the classic case — can look startlingly fresh, which is why that cargo trades well.

Manufactured “sea wear” usually overdoes it. Uniform sandblast-style texture across both sides, acid-bitten fields with no directional pattern, or heavy corrosion sitting on top of crisp modern-looking edges are all inconsistent with a coin that sat in a reef for centuries.

What are the recurring counterfeit and misattribution patterns?

The date and the assayer initial are the two most valuable characters on a cob, which makes them the two most frequently improved. Look at both under 10x magnification.

What should you do before you pay?

Frequently asked questions

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