gemstone

Agate

Silicon dioxide (Chalcedony), SiO2

Hardness: 6.5-7 on Mohs scale; Color: Brown, amber, translucent with banding; Luster: Waxy to vitreous; Crystal structure: Trigonal (microcrystalline quartz); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.64

Hardness: 6
Color: Brown, amber, translucent with banding
Luster: Waxy to vitreous

Identified August 4, 2026More gemstone →

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Physical properties

Formation & geological history

Forms in cavities of volcanic and metamorphic rocks through the deposition of silica-rich groundwater solutions in concentric layers over millions of years.

Uses & applications

Used in jewelry, ornamental carvings, lapidary art, and precision instruments.

Geological facts

Agate is one of the most popular materials used in lapidary arts due to its durability and variety of vibrant colors and patterns.

Field identification & locations

Can be identified in the field by its conchoidal fracture, waxy luster, and distinctive translucent banding. Commonly found in ancient volcanic regions and river gravels.