sedimentary
Brown Agate
Silicon Dioxide (SiO2)
Hardness: 6.5-7 (Mohs scale); Color: Variegated shades of brown, tan, and cream; Luster: Vitreous to waxy; Crystal structure: Hexagonal (cryptocrystalline); Cleavage: None, conchoidal fracture; Specific gravity: 2.58-2.64
- Hardness
- 6
- Color
- Variegated shades of brown, tan, and cream
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Variegated shades of brown, tan, and cream; Luster: Vitreous to waxy; Crystal structure: Hexagonal (cryptocrystalline); Cleavage: None, conchoidal fracture; Specific gravity: 2.58-2.64
Formation & geological history
Formed in voids of volcanic rocks or ancient sedimentary formations through the slow deposition of silica from groundwater. This specimen appears water-worn or tumbled, likely from an alluvial deposit.
Uses & applications
Commonly used for lapidary work, jewelry (beads and cabochons), home decor, and spiritual/metaphysical collecting.
Geological facts
Agate is a variety of chalcedony that is defined by its banding or variegated patterns. Humans have used agate since the Neolithic era for ornaments and amulets.
Field identification & locations
Identify in the field by its translucency (when held to light), waxy feel, and lack of visible grains. Common in riverbeds and coastal areas globally.
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