sedimentary
Agatized Fossil (Druzy Agate)
Silicon Dioxide (SiO2) replacing organic matter
Hardness: 6.5-7 Mohs; Color: Brown, tan, and translucent amber; Luster: Vitreous to waxy; Texture: Microcrystalline with druzy crystals; Cleavage: None/Conchoidal fracture.
- Hardness
- 6
- Color
- Brown, tan, and translucent amber
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 Mohs; Color: Brown, tan, and translucent amber; Luster: Vitreous to waxy; Texture: Microcrystalline with druzy crystals; Cleavage: None/Conchoidal fracture.
Formation & geological history
Formed through permineralization where silica-rich groundwater replaces organic structures or fills cavities in sedimentary layers, typically over millions of years (often Jurassic to Eocene).
Uses & applications
Used primarily for lapidary work, jewelry making (cabochons), and as educational or collectible geological specimens.
Geological facts
This specimen shows druzy quartz crystals lining an internal cavity, which is common in agatized fossils where the original biological material has been completely replaced by mineral.
Field identification & locations
Identify by its waxy exterior luster, hardness (won't scratch with a steel knife), and the crystalline interior. Commonly found in riverbeds or eroded sedimentary outcrops.
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