mineral
Quartz Geode Fragment
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 7 on Mohs scale; Color: Clear to white (milky); Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Clear to white (milky)
- Luster
- Vitreous (glassy)
Identified More mineral →
Explore Quartz Geode Fragment in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 on Mohs scale; Color: Clear to white (milky); Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed in cavities within volcanic or sedimentary rocks where hydrothermal fluids or groundwater deposit silica layers over millions of years, often during the Cenozoic or Mesozoic eras.
Uses & applications
Used in gemstone collecting, home decor, and educational displays. Industrial quartz is used in electronics (oscillators) and glassmaking.
Geological facts
Geodes are often called 'thunder eggs' in certain regions. The word geode comes from the Greek word 'geoides' meaning earth-like.
Field identification & locations
Identify by the hollow center lined with inward-pointing crystals and a rough, drab outer 'rind'. Found commonly in desert regions like Morocco, Brazil, and the Midwestern United States (Keokuk area).
