Mexican hot Aztec Calendar Brooch / Pendant, Eagle Mark, Green Quartz Sterling Silver

This vintage brooch or pendant is signed "Sterling 925 Mexico" with a maker's mark that looks like EME and the eagle mark with the numeral 83. The marks date it to the 1955 - 1970 period. The brooch has a rollover safety clasp and a bale that allows it hot to be also worn as a pendant. It is exceptionally attractive with a circular green quartz topped with a silver Aztec calendar, bezel set in sterling silver with double twisted wire frames. The brooch has a diameter of 1 3/8 inches and is approximately 1/4 inches deep. It is in excellent vintage condition.