100 Pesos Coahuila Silver Coin (2005): Value & Prices

If you inherited or found a chunky two-tone 100 Pesos coin marked "Coahuila" and dated 2005, here is the fast answer: it is a genuine collector coin, and the silver core gives it a value floor well above face. Most examples trade from a few dollars up to roughly 30 to 40 USD, with sealed mint packaging pushing the top end higher.

This is not a coin that will retire you. But it is worth more than the 100 pesos stamped on it, and the reason is silver plus a limited collector series.

What you actually have

The 2005 100 Pesos Coahuila belongs to a Mexican commemorative program marking the 180th anniversary of the union of the states into a federation. Each Mexican state got its own coin, and Coahuila is one of them. This particular issue is the second (cultural) stage of the series, with a reverse showing a cultural motif tied to the state.

Collectors sometimes call these "the state coins" or the "$100 Estados" series. There are two things that make this coin more than pocket change: the bimetallic construction with a silver center, and the fact that it was struck as a commemorative rather than for everyday circulation.

Specifications (verify yours against these)

Feature	Detail
Denomination	100 Pesos
Year	2005
Weight	33.94 grams
Diameter	39 mm
Composition	Bimetallic (silver center ring, base-metal outer)
Edge	Interrupted reeded
Series	180th Anniversary of the Federation, cultural stage

The silver center is what sets a hard floor under the value. Even a worn, damaged example is worth its metal content, which is why you will not find one selling for just 100 pesos.

How much is it worth in USD

Value comes down to condition and whether you still have the original Banco de México packaging.

Condition	Approximate value (USD)
Circulated, handled	8 to 15 USD
Uncirculated, no packaging	15 to 25 USD
Sealed in original mint blister	30 to 45 USD

These are collector ranges, not guarantees. A single common issue in average shape sits near the bottom. The premium comes from a clean, uncirculated surface and, above all, the sealed mint blister that Banco de México shipped these in. Once that seal is broken, the coin drops a tier.

Do not confuse this with the silver bullion issues Mexico is famous for, like the Onza Libertad, which track the silver spot price much more directly. The Coahuila coin is a commemorative with a fixed collector market.

The myth: "old two-tone coin, must be a fortune"

A 2005 coin is not old, and being bimetallic does not make it rare. There were 33 state coins in this program, and they turn up regularly at auction and in dealer inventory. Anyone telling you a single 100 Pesos Coahuila is worth hundreds or thousands of dollars is selling hype. The real ceiling for a standard example is the mint-sealed price above.

Where real premiums do appear: genuine, verifiable mint errors. Off-center strikes, die rotation, doubling and legitimate die varieties can multiply the value of any coin. The catch is that most "errors" people post online are post-mint damage: dings, corrosion, cleaning marks. Those lower value, they do not raise it. If you think you have a true error, get it looked at before you assume.

How to tell if yours is genuine

Counterfeits of Mexican bimetallic coins do exist, and they are easy to catch with two tools:

1. Weigh it. A genuine coin is 33.94 grams. A jewelry scale that reads to 0.01 g will expose a fake fast.
2. Measure the diameter. It should be 39 mm. Use calipers, not a ruler.
3. Check the strike. Genuine coins have sharp relief and clean separation between the silver center and the outer ring. Flat detail, blurry lettering or smeared color between the two metals are red flags.

If the weight and diameter are off, or the two metals look wrong together, treat it as suspect. Compare against the coin grading guide to place your example on the condition scale before you price it.

Where to sell it

You have a few honest options:

• A verified numismatic dealer from the Pesoteca directory, which will appraise and buy on the spot without middleman markups.
• The Pesoteca buy-and-sell forum, where you deal directly with collectors who want this exact series.

Before you sell, photograph the obverse, the reverse and the edge in good light, and check the range in the table above so you know what a fair offer looks like. Skip dumping it to the first bidder on a random social feed.

Got a 2005 Coahuila coin, or another state from this series you want valued? Post clear photos in the Pesoteca forum and the community will help you pin down the grade and a fair number.

The entry dedicated to Coahuila belongs to the first wave of the Cultural phase, issued in 2005 along with most of the set. Banxico called this second stage "Emblematic Motifs" and replaced the state coat of arms with a specific cultural symbol.

The reverse of the piece shows the umbrella-shaped pool of Cuatro Ciénegas, a formation of blue pools with living stromatolites carrying more than 3.5 billion years of evolutionary lineage. Cuatro Ciénegas is an oasis in the middle of the Chihuahuan desert, designated a Flora and Fauna Protection Area in 1994. Its pools, fed by underground springs, harbor unique endemic species such as the box turtle and pupfish that evolved in isolation from the rest of the world. The stromatolites are living colonies of cyanobacteria, witnesses to the primitive atmospheric oxygen.

State context: Coahuila was established as a state on May 21, 1824. Its capital, Saltillo, was the seat of the viceregal government of the New Spanish north. Francisco I. Madero launched the Plan de San Luis from Piedras Negras in 1910, setting off the Mexican Revolution.

In the Mexican numismatic market the Cultural phase circulated less than the 2003 Coat of Arms phase and today is usually found in higher grades because it reached the street late. Banxico's official mintages for this piece are not always published in the Economic Information System, but the figure reported to circulation tends to hover around 250,000 pieces per state in the Cultural phase. Always confirm against the catalog of the complete 100 pesos States series before closing a large purchase.

The Coahuila 2003 Coat of Arms sister is part of the first phase of the series, with the state's official coat of arms on the reverse. Landing both pieces completes the set dedicated to Coahuila.