100 Pesos Silver 2005: Centennial of the 1905 Monetary Reform

If you found a large silver Mexican coin marked "100 Pesos" and dated 2005, here is the honest answer: it is a commemorative silver piece with a real floor at its metal value. It contains 33.967 grams of .999 fine silver, roughly one troy ounce, so in 2026 it is worth at least its silver melt value, and more if it is in top condition.

This is not a coin that trades for thousands. It is a modern commemorative struck by the Casa de Moneda de México (the Mexican Mint), and thousands of collectors already own one. What gives it a solid value floor is the silver itself, not extreme rarity.

What this coin actually is

The 100 Pesos struck in 2005 marks the centennial of the Reforma Monetaria de 1905, the 1905 Monetary Reform. That reform reset Mexico's currency system and tied the peso to a gold standard, moving away from the silver standard that had run for decades. A century later, the Bank of Mexico (Banxico) issued this silver commemorative to mark the anniversary.

The technical facts you can check on your own coin:

• Metal: .999 fine silver (99.9% pure)
• Weight: 33.967 grams (about 1.09 troy ounces)
• Diameter: 39 mm
• Edge: interrupted reeding
• Year: 2005 only, a single-year issue
• Mint: Casa de Moneda de México

What it is worth in USD

Because it holds about one ounce of pure silver, its baseline value tracks the live silver spot price. When silver trades around 30 USD per ounce, the metal alone is worth roughly that much. A coin with wear or handling marks tends to sell near melt. A clean, uncirculated example, or one certified in a high grade, brings a premium above melt because collectors pay for eye appeal on silver, where every scratch shows.

Honest range: from silver melt value on a handled piece up to a modest premium on a pristine or graded example. This is a bullion-plus-collectible coin, not a rarity that commands a fortune. Anyone telling you a common modern silver commemorative is worth thousands is selling hype.

Rarity: what we actually know

Banxico did not publish an official mintage figure for this issue, which usually means it came out in limited numismatic sets or a small, specific run. Collector forums float numbers, but none are confirmed. Absence of a published mintage is not proof of great rarity. Treat any unsourced figure with skepticism. What is certain is the single year of issue, 2005, so there are no year varieties to chase within this release.

How to tell if yours is genuine

Silver coins get counterfeited, so verify before you buy or sell:

• Weigh it. A genuine coin weighs 33.967 grams. If yours is meaningfully off, be cautious.
• Measure it. Diameter should be 39 mm.
• Check the relief. Fakes tend to have flat, soft detail. Compare against official Banxico images of the design.
• Look at the edge. It should show interrupted reeding.
• Get it certified for anything you plan to sell at a premium. NGC or PCGS grading is the definitive proof of authenticity and condition, and a graded coin always sells for more than a self-assessed one.

Most "error coins" people post online are post-mint damage (dings, corrosion), not genuine minting errors. A real, verified error (off-center strike, die rotation, doubled die) can raise value, but it needs expert confirmation.

Where to sell it

Since the value is tied to silver content, sell only where the buyer can see and weigh the coin:

• A verified numismatic shop in the Pesoteca directory will appraise it on the spot at a fair price.
• The Pesoteca buy-and-sell forum connects you directly with collectors.
• Coin shows and precious-metal dealers will at least pay you melt value for the silver.

Photograph the front, back, and edge before you list it. Compare against the range on this page so you know what a fair offer looks like, and do not dump it on the first social-media bidder.

Have a 2005 silver 100 Pesos in hand and not sure what it grades? Post clear photos of both sides and the edge in the Pesoteca forum and let collectors help you pin down its condition and value.

The Monetary Reform of 1905 established the gold standard in Mexico under the government of Porfirio Díaz. The reform tied the peso to gold at a fixed parity, reorganized the minting, and gave way to the Hidalgo Gold series (Centenario 50, Azteca 20, Hidalgo 10, 5, 2.5, and 2 pesos). This piece commemorates the centennial of that reform. Banxico's quarterly SM report marks 0 pieces in circulation because it was an edition exclusively for collectors in a commemorative case.