gemstone

Agate

Silicon Dioxide (Chalcedony variety, $SiO_2$)

Hardness: 6.5-7 on the Mohs scale. Color: White, gray, translucent with banded patterns. Luster: Waxy to vitreous. Crystal structure: Trigonal (microcrystalline quartz). Cleavage: None. Specific gravity: 2.60-2.65.

Hardness: 6
Color: White, gray, translucent with banded patterns
Luster: Waxy to vitreous

Identified July 28, 2026More gemstone →

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Physical properties

Formation & geological history

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

Uses & applications

Used for ornamental carvings, jewelry, metaphysical purposes, and as a decorative collector's item.

Geological facts

Agate is one of the most popular and versatile stones for lapidary work due to its durability and striking natural banding.

Field identification & locations

Easily identified by its characteristic curved or concentric banding and waxy luster. Found worldwide, notably in Brazil, India, Madagascar, and the United States.

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