metamorphic
Banded Quartzite
Quartzite (SiO2 with impurities)
Hardness: 7 on Mohs scale; Color: Cream, tan, and white bands; Luster: Vitreous to waxy (especially when water-worn); Crystal structure: Hexagonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.6 - 2.7.
- Hardness
- 7 on Mohs scale
- Color
- Cream, tan, and white bands
- Luster
- Vitreous to waxy (especially when water-worn)
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Physical properties
Hardness: 7 on Mohs scale; Color: Cream, tan, and white bands; Luster: Vitreous to waxy (especially when water-worn); Crystal structure: Hexagonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.6 - 2.7.
Formation & geological history
Formed through the regional metamorphism of quartz-rich sandstone. Under intense heat and pressure, original quartz grains and silica cement recrystallize into an interlocking mosaic. This specimen has been further shaped and smoothed by fluvial or coastal erosion.
Uses & applications
Used primarily as decorative stone, aquarium gravel, crushed stone for road construction, and occasionally for minor lapidary work (tumbling/polishing).
Geological facts
Quartzite is so durable that it often remains as resistant hills or ridges (monadnocks) after surrounding softer rocks have eroded away. The distinct banding often represents the original sedimentary bedding of the parent sandstone.
Field identification & locations
Identify in the field by its superior hardness (cannot be scratched by a steel pocket knife) and its grainy, 'sugary' texture visible under a loupe. Commonly found on high-energy beaches, terminal moraines, and riverbeds in glaciated regions.
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