gemstone

Opal

Hydrated amorphous silica (SiO2·nH2O)

Hardness of 5.5-6.5 on the Mohs scale, milky or translucent color with play-of-color, subvitreous to greasy luster, and amorphous crystal structure.

Identified October 20, 2026More gemstone →

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Physical properties

Hardness of 5.5-6.5 on the Mohs scale, milky or translucent color with play-of-color, subvitreous to greasy luster, and amorphous crystal structure.

Formed from a solution of silicon dioxide and water seeping into cracks and voids in sedimentary or volcanic rock over millions of years.

Extensively used in high-end jewelry, including rings, necklaces, and collector displays.

Opal contains up to 20% water trapped within its microscopic silica spheres, which diffract light to create its signature rainbow flashes.

Easily identified by its characteristic play-of-color and lack of crystal cleavage; commonly found in Australia, Ethiopia, and Mexico.

Ammolite

Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)

Gemstone Ring

N/A - Set piece of jewelry, likely Amethyst or Garnet with Diamond or CZ

Amber

Succinite (Organic Gemstone)

Diamond and Gold Jewelry

Carbon (Diamond) / Au (Gold)

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Pearl necklace

Pearl, primarily aragonite (CaCO₃) and conchiolin