gemstone

Tumbled Agate

Silicon Dioxide (Chalcedony variety), SiO2

Hardness: 6.5 to 7 on the Mohs scale; Color: Tan, beige, brown, and translucent white banding; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microcrystalline quartz); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58 to 2.64

Hardness: 6
Color: Tan, beige, brown, and translucent white banding
Luster: Waxy to vitreous

Identified July 28, 2026More gemstone →

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Physical properties

Formation & geological history

Formed by the deposition of silica from groundwater in the cavities of igneous and sedimentary rocks, typically occurring over millions of years.

Uses & applications

Used primarily in lapidary arts, tumbled stones, decorative ornaments, jewelry, and gemstone collecting.

Geological facts

Agate has been used since antiquity for ornaments, seals, and healing talismans, with famous archaeological discoveries in ancient Crete and Egypt.

Field identification & locations

Identified by its microcrystalline structure, waxy luster, and concentric banding patterns; commonly found worldwide in volcanic rock cavities and river gravels.

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