100 Pesos Bimetallic 2004 (180th Anniversary): Value & Silver Content

If you inherited or found a Mexican 100 pesos bimetallic coin dated 2004 with "180 Aniversario" on it, here is the honest answer: most of these trade in the range of 20 to 60 USD, driven mostly by their silver center. This is a collector commemorative, not a rare payday, but it is worth real money and worth checking carefully before you sell.

This piece is part of a Mexican mint program celebrating the 180th anniversary of the union of the states into a federation. It was struck at the Casa de Moneda de México (the Mexican Mint, in continuous operation since the 16th century) and cataloged as KM# 700.

What this coin actually is

The 2004 100 pesos is a bimetallic commemorative: a coin made of two metals, a ring of one metal around a center of another, the same layout you see on many world coins. "Bimetálica" is just the Spanish word for bimetallic.

Here are the exact specs, which matter for spotting fakes and for grading:

Spec	Value
Denomination	100 pesos
Year	2004
Type	Bimetallic commemorative
Weight	29.17 g
Diameter	34.5 mm
Edge	Plain (smooth)
Finish	Proof (mirror fields, satin relief)
Catalog	KM# 700
Mint	Casa de Moneda de México

The proof finish (mirror-like background with frosted raised designs) tells you this was made for collectors, not for circulation. Proof coins were sold in official mint packaging, so a coin still in its capsule or original set is worth more than a loose, handled one.

Is it silver? What it's worth at melt

The center of many of these commemorative 100 pesos coins is .999 fine silver, which puts a floor under the value. That is why even a common example does not drop to face value. The bullion floor typically works out to roughly 20 USD or more depending on the silver spot price, so no one should ever offer you less than melt for one.

On top of the silver, the collector premium for a nice proof example in its original packaging pushes the realistic market range to about 20 to 60 USD. Certified high-grade examples (NGC or PCGS graded PF 68 to PF 70) can bring somewhat more, but this is not a coin that reaches hundreds or thousands of dollars in normal condition.

The "it must be worth a fortune" myth

A large-diameter, heavy coin with gold-colored and silver-colored metal looks expensive. It is not rare. Mexico struck a whole series of these state and anniversary commemoratives in the 1990s and 2000s, and they show up regularly. If a listing or a video tells you a 2004 100 pesos is worth thousands, treat that as clickbait. The real driver here is the silver content plus a modest collector premium.

Where value can jump is a genuine, verifiable mint error (off-center strike, die rotation, double strike). Real errors are scarce and can multiply the price. But most "errors" people post online are post-mint damage: dings, scratches, corrosion. Those lower value, they do not raise it. If you think you have a true error, get it looked at before you celebrate.

How to tell if yours is genuine

1. Weigh it. A jewelry scale should read very close to 29.17 g. Fakes are commonly off on weight.
2. Measure it. Diameter should be 34.5 mm. Use calipers.
3. Check the edge. It should be plain and smooth, no reeding.
4. Look at the strike. A real proof has sharp, satin-frosted designs against mirror fields. Flat, mushy relief or colors that bleed between the ring and center are red flags.

If the weight and diameter are both correct and the finish looks right, you almost certainly have a genuine piece.

Where to sell it (and get a fair price)

• Take clear photos of the front (obverse), back (reverse), and edge, plus the original capsule or packaging if you have it.
• Compare against the range in this listing before you accept any offer.
• Sell through a verified coin dealer or a numismatic marketplace where collectors, not flippers, are bidding. Certified (slabbed) examples sell faster and for more.
• Skip selling to the first random buyer on social media. For a silver-content coin, insist on at least the melt value as a floor.

If you have several inherited Mexican coins and are not sure which ones carry a premium, post photos in the Pesoteca forum and the community will help you sort the silver from the pocket change.