mineral

Brown Agate

Silicon Dioxide (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Brown, tan, and white translucent bands/patches; Luster: Waxy to vitreous when polished; Crystal structure: Hexagonal (trigonal) microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.64.

Hardness: 6
Color: Brown, tan, and white translucent bands/patches
Luster: Waxy to vitreous when polished

Identified May 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater into cavities (vesicles) in igneous rocks or fissures in sedimentary rocks. Often millions of years old, appearing in volcanic host rocks.

Uses & applications

Commonly used for lapidary work, jewelry (beads, cabochons), home decor, and spiritual/metaphysical collecting.

Geological facts

Agate is a variety of chalcedony distinguished by its banding patterns. The brown color is often caused by the presence of iron oxides like limonite or goethite.

Field identification & locations

Identify in the field by its translucency and waxy texture. Commonly found in riverbeds, glacial tills, and volcanic regions globally (notably Brazil, India, and the Lake Superior region of the US).