mineral
Quartz (specifically a water-worn Quartzite or Chalcedony pebble)
Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: Tan, brown, or translucent beige; Luster: Waxy to vitreous; Crystal Structure: Trigonal (often microcrystalline as chalcedony or massive in quartzite); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Tan, brown, or translucent beige
- Luster
- Waxy to vitreous
Identified More mineral →
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Physical properties
Hardness: 7 on Mohs scale; Color: Tan, brown, or translucent beige; Luster: Waxy to vitreous; Crystal Structure: Trigonal (often microcrystalline as chalcedony or massive in quartzite); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed through the crystallization of silica-rich fluids or the metamorphism of sandstone. This specific specimen has been significantly eroded and smoothed by mechanical action in water (river or beach environment).
Uses & applications
Raw quartz is used in glass making, abrasive manufacturing, electronics (due to piezoelectricity), and as a gemstone when high quality. Tumbled pebbles are common in landscaping and decorative aquariums.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. Specimens found as smooth pebbles have often traveled miles from their original source via riverbeds or glacial movement.
Field identification & locations
Identify in the field by its inability to be scratched by a steel pocketknife and its lack of visible layers. Look for it along river banks, shorelines, or gravel pits worldwide.
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Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Schist
Schist
Metamorphic
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock
Banded Gneiss (River Rock/Pebble)
Gneiss (specifically a banded variety often found as a river rock)
Metamorphic Rock