metamorphic
Orange Quartzite (or Quartz River Pebble)
Silicon Dioxide (SiO2) - Quartzite
Hardness: 7 on Mohs scale. Color: Pale orange to yellowish-tan due to iron oxide impurities. Luster: Vitreous to waxy. Crystal structure: Hexagonal (trigonal) cryptocrystalline structure. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- Pale orange to yellowish-tan due to iron oxide impurities
- Luster
- Vitreous to waxy
Identified More metamorphic →
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Physical properties
Hardness: 7 on Mohs scale. Color: Pale orange to yellowish-tan due to iron oxide impurities. Luster: Vitreous to waxy. Crystal structure: Hexagonal (trigonal) cryptocrystalline structure. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone. Under intense heat and pressure, the sand grains recrystallize and fuse together. The orange coloration usually comes from iron staining during or after formation.
Uses & applications
Used primarily as decorative landscaping stone, in construction aggregates, or as a source of silica. Tumbled versions are common in beginner rock collections.
Geological facts
Quartzite is so tough that it often outlasts the surrounding rock layers during erosion, frequently ending up as smoothed river pebbles like the one shown here.
Field identification & locations
Identify in the field by its hardness (it will scratch glass) and its grainy, sugary texture when broken. Common in riverbeds, glacial deposits, and metamorphic mountain belts worldwide.
