Description
Unique with play-of-color flashes. Hydrous silica wonder. Specs: Weight 2-8 carats. Opal, a crystalline gem mineral, takes form through the solidification of gelatinous or liquid silica within cracks and voids, often created by decaying organic matter, wood, crustaceans, and bones. Its highest value resides in its “black” forms, embodying a significant water content. Represented by SiO2 plus H2O, opals can encompass up to 10% water content, boasting a refractive index that ranges from 1.38 to 1.60. On the Mohs’ scale, opals register a hardness of 5.5 to 6.5.
