mineral
Quartz Pebble (Citrine or Iron-Stained Quartz)
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 7 on Mohs scale; Color: Pale yellowish-translucent with milky zones; Luster: Vitreous to waxy (water-worn); Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: ~2.65.
- Hardness
- 7 on Mohs scale
- Color
- Pale yellowish-translucent with milky zones
- Luster
- Vitreous to waxy (water-worn)
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Physical properties
Hardness: 7 on Mohs scale; Color: Pale yellowish-translucent with milky zones; Luster: Vitreous to waxy (water-worn); Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: ~2.65.
Formation & geological history
Formed in hydrothermal veins or pegmatitic igneous environments, subsequently weathered, eroded, and smoothed into a rounded pebble by river, stream, or beach wave action.
Uses & applications
Commonly tumbled for lapidary crafts, wire-wrapped jewelry, or collected as river tumble specimens; quartz also serves critical functions in electronics, abrasives, and glass manufacturing.
Geological facts
Naturally yellow quartz (citrine) gets its color from trace ferric iron (Fe3+) impurities within the crystal lattice, though many surface-collected yellow quartz pebbles obtain their hue from secondary iron oxide coatings penetrating micro-fractures.
Field identification & locations
Identified in the field by its hardness (scratches glass and steel knife blades), lack of true cleavage, translucent to semi-transparent nature, and smooth water-worn surface; universally found in gravel beds, rivers, and coastal beaches.
