Rock Identifier
Agate (Silicon Dioxide (Chalcedony), SiO2) — gemstone
gemstone

Agate

Silicon Dioxide (Chalcedony), SiO2

Hardness of 6.5 to 7 on the Mohs scale, varied colors due to impurities, waxy to vitreous luster, cryptocrystalline crystal structure, conchoidal fracture with no true cleavage, specific gravity of 2.58-2.64.

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Physical properties

Hardness of 6.5 to 7 on the Mohs scale, varied colors due to impurities, waxy to vitreous luster, cryptocrystalline crystal structure, conchoidal fracture with no true cleavage, specific gravity of 2.58-2.64.

Formation & geological history

Formed mainly in cavities of volcanic rocks or ancient lavas through the slow deposition of silica-rich groundwater solutions over millions of years.

Uses & applications

Used in jewelry, ornamental carvings, decorative items, and historically for precision instruments like mortar and pestles.

Geological facts

Agate is one of the most popular stones used in art and healing, often exhibiting distinct concentric banding formed by alternating layers of chalcedony.

Field identification & locations

Identified by its waxy luster, conchoidal fracture, and characteristic banding or translucency. Found worldwide in volcanic and sedimentary regions.

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