100 Pesos Guanajuato (Cultural) 2005: Value & Silver Content

If you inherited a heavy two-tone Mexican 100 pesos coin dated 2005 with Guanajuato on it, here is the honest answer: the loose coin is worth roughly 25 to 45 USD, mostly because of the silver in its center. A complete, sealed proof set can bring more. It is a collectible commemorative, not a rare treasure, but it is not pocket change either.

This is the 100 Pesos Guanajuato coin from the series marking the 180th anniversary of the union of the Mexican states into a federation (in Spanish, "Unión de los Estados en una Federación"). Each Mexican state got its own coin, and this one, from the second cultural phase, carries a design representing Guanajuato.

What it actually is

This is a bimetallic (two-metal) commemorative, and that matters for value. The outer ring is base metal, but the center core is .925 silver, which is what gives the coin a real floor price above face value.

Feature	Detail
Denomination	100 pesos
Year	2005
Weight	33.94 grams
Diameter	39 mm
Composition	Bimetallic, .925 silver center
Edge	Discontinuous reeded
Finish	Satin (some pieces issued as proof in sets)
Series	180th Anniversary of the Federation

Obverse (front): The Mexican national coat of arms, an eagle devouring a serpent on a cactus. This face is shared across the entire 100 pesos state series.

Reverse (back): A cultural motif representing Guanajuato, which may show architecture, an archaeological site, flora, fauna, or traditional dress. This is the design from the second phase of the series. Check the exact reverse design against the official Banxico catalog before you catalog your piece, since the state series has several variants.

What it's worth in 2026

Most of the value here comes from the silver center, not from rarity. These coins were minted in the millions relative to true rarities, so you are dealing with a solid collectible, not a five-figure coin.

Condition	Approximate value (USD)
Circulated, loose	20 to 30
Uncirculated, loose	30 to 45
Original Banxico blister/proof set	50 to 90+

The biggest jump in value comes from the original Banxico packaging. Collectors pay a premium for a coin still sealed in its official blister or as part of a complete proof set. A loose coin that has been handled sells for the silver-plus-collector floor and little more.

The myth to kill

Social media posts claim these state coins are worth thousands. They are not, unless you have a verified minting error. A normal 2005 Guanajuato 100 pesos in average shape is a 25 to 45 USD coin. Do not let a Facebook "buyer" convince you it is worthless (they are lowballing the silver), and do not expect a fortune either.

How to check what yours is worth

1. Weigh and measure it. Use a jewelry scale and a caliper. It should hit 33.94 grams and 39 mm. Off numbers point to a fake or a damaged piece.
2. Grade the condition. Scratches, wear, and cleaning all lower value. See our coin grading guide to judge yours honestly.
3. Look for the original packaging. A sealed Banxico blister or proof set is worth more than a loose coin.
4. Rule out damage vs. error. Most "errors" people post online are post-mint damage, not factory errors. A genuine off-center strike, die rotation, or double strike can add real money, but it has to be verified.

Where to sell it

For the best price, use a verified numismatic shop from the Pesoteca directory, where a dealer values it on the spot without a middleman markup, or list it in the Pesoteca buy-and-sell forum among collectors. Photograph the obverse, reverse, and edge, and check the value range on this page before you accept any offer. Skip dumping it to the first bidder on social media.

Have a 2005 state series coin you are trying to identify or price? Post clear photos in the Pesoteca forum and let collectors confirm the variant and condition for you.

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

The reverse of the piece shows the Alhóndiga de Granaditas, a viceregal granary completed in 1809 where El Pípila set fire to the gate on September 28, 1810. The taking of the Alhóndiga was the first armed victory of the insurgent army led by Miguel Hidalgo. Juan José de los Reyes Martínez, El Pípila, covered his back with a stone slab and set fire to the gate that sheltered the royalist troops. Today the Alhóndiga is a regional INAH museum and a seat of the University of Guanajuato, with its monumental staircase at the front.

State background: Guanajuato was established as a state on December 20, 1823. The colonial Go mint operated from 1812 to 1900, striking 8-real silver pieces from the Valenciana and La Cata mines, and it was one of the three large mints of the viceroyalty alongside Mexico and Zacatecas.

In the Mexican numismatic market the Cultural phase circulated less than the 2003 Escudo and today is usually found in higher grades because it reached the streets 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 be 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 sister 2003 Escudo of Guanajuato belongs to the first phase of the series, with the state's official coat of arms on the reverse. Hunting both pieces completes the set dedicated to Guanajuato.