Natural Oval Simbercite gemstone sterling pendant, 50mm x 27mm, 6mm thick. Highly polished, excellent quality cabochon stone. With sterling bail and three strand black leather cord, sterling end caps and lobster claw clasp. Simbercite with pyrite is both a gemstone and fossil. This is a really unique stone and you'll rarely see them in today's jewelry market because they are rare. Simbercite or Simbircite from the Russian city of Simbirsk (now Ulianovsk) is one of those jaw-dropping gemstones that leave everyone breathless. It is a conglomerate of calcite, marl, pyrite, and fragments of ammonites and other ancient sea life forms. They are beautiful, rich in colors of amber, with shades of brown, white, red or green. It is an agatized material that fills in chambers of the Ammonite Lamberticeras sp. with a complex mix of iron magnesium rich calcite (????3), aragonite, pyrite, marl, chabazite and quartz. The veins of pyrite which you see as a gold to silver colored bands, were originally the bone of the ammonite. Formed over 160 million years ago. * Oval Simbercite Pyrite Gemstone Cabochon Sterling Pendant. * Sterling bail, end caps, and lobster claw clasp. * Black leather cord, 16 inch, adjustable to 17 and 18 inch.