1 Kilo Silver Aztec Calendar 100 Pesos (2015): What It's Worth

If you inherited or found a heavy Mexican silver coin marked "100 Pesos" with the Aztec Calendar (Sun Stone) on it, you have something with real intrinsic value. This is a full kilogram of fine silver. In 2026, its value floor tracks the silver spot price, which puts it in the four-figure range in US dollars regardless of collector demand.

This is not a pocket-change coin. It never circulated. Mexico's central bank, Banco de México (Banxico), issued it as a bullion and collector piece struck at the Casa de Moneda de México, the national mint operating continuously since the 16th century. The "100 Pesos" face value printed on it is symbolic. Its worth comes from the metal, not the denomination.

What this coin actually is

The 2015 100 Pesos silver Aztec Calendar is a one-kilo bullion coin. Here is what matters for value:

• Metal: silver
• Weight: 1,000 grams (1 kilogram)
• Diameter: 110 mm (about 4.3 inches, larger than a coffee cup coaster)
• Edge: smooth, no reeding
• Finish: matte and shine contrast ("mate-brillo"), a proof-like relief that makes the design pop
• Design: the Aztec Calendar, also called the Sun Stone or Piedra del Sol
• Catalog reference: KM#921
• Mint: Casa de Moneda de México

A kilo of silver is a serious amount of metal. The design is a scaled-up version of the same Sun Stone that appears on the popular Onza Libertad silver rounds, which are Mexico's flagship bullion series.

How much is it worth in 2026?

The honest answer starts with math, not myth. A one-kilo silver coin has a hard value floor equal to its melt value: 1,000 grams of silver times the current spot price. When silver trades around 30 US dollars per troy ounce (roughly 0.965 dollars per gram), the raw metal alone is worth close to 1,000 US dollars. That number moves up and down every day with the silver market.

On top of the melt value, these kilo pieces carry a premium because they are minted in limited numbers, they are sought by collectors of the Aztec Calendar series, and a one-kilo coin is a novelty in its own right. In practice, well-preserved examples with their original mint capsule and certificate trade at a premium over spot, often in the range of a few hundred dollars above melt depending on condition and demand at the moment.

Coin	Year	Metal content	Typical value (USD)	Where it sells
100 Pesos Aztec Calendar, 1 kilo	2015	1,000 g silver	Around 1,000 to 1,400+, tracking silver spot	Bullion dealers, numismatic shops, collector forums

The key point: this coin has a floor. Unlike a random old copper coin worth a few dollars, a kilo of silver cannot fall below its metal value. That makes it a safer inheritance to hold than most vintage coins people ask us about.

Is it rare?

Rare in the collector sense means low survival and high demand. This piece is limited in mintage, but it is a modern bullion issue, not a scarce classic. Do not expect a life-changing figure. What you should expect is a solid four-figure value in US dollars driven mostly by the silver inside it, with a modest collector premium layered on top.

Beware of headlines claiming modern Mexican silver coins are "worth a fortune." For this piece, the fortune is the silver. Anyone quoting a five-figure number for a standard 2015 example is inflating it. The realistic ceiling for a normal specimen sits within a few hundred dollars of melt value.

How to tell if yours is genuine

Because the value is in the precious metal, fakes exist. Verify before you buy or sell:

1. Weigh it. Use a jewelry scale. It must weigh 1,000 grams. A fake or plated piece will almost always come in under weight.
2. Measure the diameter. It should be 110 mm across. Use calipers or a ruler. Wrong size is an immediate red flag.
3. Check the edge. The genuine coin has a smooth (plain) edge with no reeding.
4. Inspect the relief and finish. The authentic matte-and-shine finish gives crisp contrast. Flat, mushy detail or uneven coloring suggests a cast counterfeit.
5. Distrust deep discounts. Any offer far below the current silver melt value is a warning sign, not a bargain.

For a coin this valuable, professional authentication or grading (NGC, PCGS) is worth the fee before a large sale. A certified holder also gets you a better price from serious buyers.

Where to sell it

Because you are selling silver by weight, transparency matters more than anything.

• A verified numismatic shop from the Pesoteca directory will value it on the spot and tell you the current premium over melt.
• The Pesoteca buy-and-sell forum connects you directly with collectors, which usually beats a walk-in bullion buyer.
• A reputable bullion dealer will always pay at least melt value, so that is your safety net for a fast sale.

Photograph the obverse, reverse, and edge, note the weight, and check the value range above before you accept any offer. Never dump a kilo of silver on the first social-media buyer without confirming the day's spot price first.

What about mint errors?

Genuine, verifiable striking errors (off-center strikes, die rotation, doubling) can add value on any coin. But most "errors" people spot on modern bullion are post-mint damage: scratches, spots, or contact marks, not factory defects. If you think you have a real one, post clear photos in the Pesoteca forum and let the community weigh in before you assume a premium.

Got one of these kilo silver coins sitting in a drawer and not sure what today's silver price makes it worth? Bring your photos and weight to the Pesoteca community and get a straight answer from people who trade these regularly.