Opal is a birthstone for October, along with Tourmaline, also the gem of the 14th anniversary. Opal is the world's most popular phenomenal gem. Many cultures have credited opal with supernatural origins and powers. Arabic legends say it falls from the heavens in flashes of lightning. The ancient Greeks believed opals gave their owners the gift of prophecy and guarded them against disease. Europeans have long considered the gem a symbol of hope, purity, and truth. Opal contains up to 20% water trapped in its silica structure. Experts divide opals into many different categories, Four of the main types are:
White Opal - Play of color against a white or light gray body-color
Black Opal - Play of color against a black or other dark bodycolor Fre Opal - Doesn't show a play of color, yellow, orange, Or red body color, known as Mexican Opal, Gold Opal, Or Sun OPal
Boulder Opal - Play of color against light to a dark background. host rock fragment or metrix are part of the finished gems
Mineral: Hydrated Silica Chemistry: SiO2•nH2O Color: All colors Refractive index: 1.37-1.47 Birefringence: None Specific gravity: 2.15 ( 0.08, -0.90) Mohs Hardness: 5 to 6.5 on the Mohs scale Origin: Black & White Opal - Australia & Ethiopia white Opal - Brazil Fire opal - Mexico Treatment : Suger & Smoke, Impregnation & Assemble.
Care and cleaning: Warm soapy water is always safe. Ultrasonic and steam cleaning are not recommended.