Oval, Opal Drop Earrings with Diamond Framing in 24kt Gold by Prehistoric Works of Istanbul, Turkey. Measurements: Total Length, 20mm (.8") x 12.5 (.5"), Opal measures6.5mm x 8.4mm. Each earrings weighs 1.6 grams. The ancient Greeks believed opals gave their owners the gift of prophecy and guarded them from disease. Europeans have long considered the gem a symbol of hope, purity, and truth. Opal is considered an October birthstone.