14kt yellow gold unique Antique brooch with chrysoberyl gemstone center, opals, 1.05ct Old Mine cut diamonds & filigree bead drops. The broooch has a pendant bail on rear that folds away. Chrysoberyl is a rare, exceptionally durable gemstone that is the third-hardest natural gemstone after diamond and corundum (sapphire and ruby). Most common specimens range from lemon-yellow and golden-honey to greenish-yellow and mint green, colored primarily by trace amounts of iron. Old Mine cut diamonds usually date back to the 1700s and 1800s, before diamond cutting was perfected.