An olive-green vitreous magnesium iron silicate, also called olivine and peridot. It is crystalline and, when transparent, used as a gem. An apple-green type of chalcedony. A clear yellow quartz resembling topaz. Used for pendants, bracelets, earrings, and pins.
Precious coral is red and branching, found in the Mediterranean.
A deep-green brilliant emerald is one of the costliest of gems. The emerald is a variety of beryl. The finest stones come from Colombia. Other sources are Brazil, Egypt, Australia, Austria, Norway, and North Carolina. Feldspars are widely distributed.