mineral
Agate (Yellow Moss Agate)
Cryptocrystalline Quartz (SiO2)
Hardness: 6.5-7 on Mohs scale; Color: Yellow, tan, brownish-green; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (rhombohedral); Specific Gravity: 2.58-2.64.
- Hardness
- 6
- Color
- Yellow, tan, brownish-green
- Luster
- Vitreous to waxy
Identified More mineral →
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Physical properties
Hardness: 6.5-7 on Mohs scale; Color: Yellow, tan, brownish-green; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (rhombohedral); Specific Gravity: 2.58-2.64.
Formation & geological history
Formed primarily in volcanic and metamorphic rocks as a result of groundwater circulating through cavities (vesicles) or cracks, depositing microcrystalline silica over millions of years. This piece appears to have been water-worn or tumbled.
Uses & applications
Used extensively in lapidary arts, jewelry (cabochons, beads), decorative carvings, and as a popular specimen for collectors due to its durability and unique patterns.
Geological facts
Moss agates are not technically organic moss; their name comes from the dendritic inclusions of manganese or iron oxides that resemble botanical patterns. Agate has been used for over 3,000 years, notably by ancient Egyptians.
Field identification & locations
Identified by its translucency (when held to light), waxy luster, and lack of distinct cleavage. Often found in riverbeds, lake shores (like Lake Superior), and volcanic regions globally.
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