10 x 1 oz Aztec Calendar Copper Round .999 Fine Copper Bullion 1 AVDP Ounce These amazingly intricate and beautiful 1 oz Copper Bullion rounds of the Aztec Calendar are made by Golden State Mint and are now available in a new variety of sizes and metals. The Aztec Calendar is an amazing system of tracking days and time as well as the significance of that day and how it would be impactful in a positive or negative spiritually, religiously and personally as well as for an event or occasion. A 52 year 365-day cycle system of 18 20 day cycles that aligned with another 260-day rotation with a 13-day cycle gave every year and day a unique name and number identification. Years, Days and periods have a name and number identification like 7 rabbit 1 wind 7 reed as well as a governing diety. To our current calendar system, this all seems very complex with a lot to remember. Visually the Aztec calendar is a stunning and intricate display and as a round object itself a perfect fit for these fantastic pieces that will make a beautiful addition to any collection. Diameter (≈): 39.3 mm | 1.55" Thickness (≈): 3.31 mm | 0.130" Solid, pure .999 Fine Copper. No plating or coating.