mineral

Grey Agate

Silicon Dioxide (SiO2) - Microcrystalline Quartz

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale; Color: translucent grey to brownish-grey with subtle banding; Luster: vitreous to waxy when polished; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64.

Hardness: 6
Color: translucent grey to brownish-grey with subtle banding
Luster: vitreous to waxy when polished

Identified July 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed primarily in volcanic gas cavities (vesicles) through the deposition of silica-rich hydrothermal fluids over long periods.

Uses & applications

Popular for lapidary work, jewelry making (cabochons, beads), decorative tumbled stones, and rock collections.

Geological facts

Agate is a variety of chalcedony characterized by its fine grain and brightness of color. Grey agate is often used as a grounding stone in crystal healing practices.

Field identification & locations

Identified by its waxy luster, smooth translucent body, and subtle internal banding. Commonly found in Brazil, Uruguay, Madagascar, and the United States.