mineral

Agate

Agate (Silicon Dioxide, SiO2)

Hardness: 6.5-7 (Mohs scale); Color: White, cream, tan with micro-banding; Luster: Waxy to vitreous; Crystal Structure: Trigonal (Cryptocrystalline); Cleavage: None; Specific Gravity: 2.58-2.64

Hardness: 6
Color: White, cream, tan with micro-banding
Luster: Waxy to vitreous

Identified June 25, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: White, cream, tan with micro-banding; Luster: Waxy to vitreous; Crystal Structure: Trigonal (Cryptocrystalline); Cleavage: None; Specific Gravity: 2.58-2.64

Formation & geological history

Formed as a secondary mineral in volcanic or metamorphic host rocks, specifically through the deposition of silica from groundwater into cavities (vesicles) or cracks. Common in Cenozoic and Mesozoic deposits.

Uses & applications

Used for jewelry (cabochons), interior decor, artistic carvings, and industrial precision tools like mortars/pestles due to its hardness and chemical resistance.

Geological facts

Agate is a variety of chalcedony characterized by its concentric banding. Historically, it was used for amulets in ancient Greece and Rome. Most commercial agates are dyed, but this specimen appears natural.

Field identification & locations

Identify by looking for fine, concentric band patterns and a waxy texture. Commonly found in riverbeds, gravel pits, and volcanic regions. Collectors look for unique banding and clarity.