metamorphic
Quartzite Pebble
Quartzite (primarily SiO2)
Hardness: 7 on Mohs scale; Color: Tan to light brown with grayish inclusions; Luster: Vitreous to dull/waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.6 - 2.8
- Hardness
- 7 on Mohs scale
- Color
- Tan to light brown with grayish inclusions
- Luster
- Vitreous to dull/waxy
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 on Mohs scale; Color: Tan to light brown with grayish inclusions; Luster: Vitreous to dull/waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.6 - 2.8
Formation & geological history
Formed through the regional or contact metamorphism of quartz-rich sandstone. High heat and pressure Recrystallize quartz grains into a dense, interlocking matrix. This specific specimen appears to be a water-worn river pebble, shaped by fluvial transport over millions of years.
Uses & applications
Industrial uses include glassmaking, abrasive blasting, and as a source of high-purity silica. In construction, crushed quartzite is used for road ballast and decorative landscaping. Polished pebbles are used in ornamental gardens or as 'worry stones'.
Geological facts
Quartzite is so durable that it often survives intense weathering and erosion that destroys other rocks. While sandstone feels gritty to the touch, true quartzite will break through the quartz grains rather than around them, resulting in a smoother, glassier surface.
Field identification & locations
Identify in the field by its inability to be scratched by a steel pocket knife and its lack of reaction to acid. Commonly found in riverbeds, glacial deposits, and mountain ranges. For collectors, look for smoothness and translucency.
More like this
