metamorphic
Quartzite Pebble
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: white to light gray; Luster: sugary or vitreous; Crystal structure: Non-foliated interlocking quartz grains; Specific gravity: 2.6-2.7. Highly resistant to scratching.
- Hardness
- 7 on Mohs scale
- Color
- white to light gray
- Luster
- sugary or vitreous
Identified More metamorphic →
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Physical properties
Hardness: 7 on Mohs scale; Color: white to light gray; Luster: sugary or vitreous; Crystal structure: Non-foliated interlocking quartz grains; Specific gravity: 2.6-2.7. Highly resistant to scratching.
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone under intense heat and pressure, typically during mountain-building events (orogeny). This specific piece is a water-worn river pebble.
Uses & applications
Used in construction as crushed stone or road ballast, as a raw material for glass making, in ceramics, and often used as decorative landscaping stones due to its durability.
Geological facts
Quartzite is so tough that it often outlasts the mountain ranges where it was formed, persisting as durable pebbles in rivers and on beaches long after other rocks have eroded away.
Field identification & locations
Identified by its extreme hardness (cannot be scratched by a steel knife) and its grainy, 'sugary' texture on fresh surfaces. Commonly found in riverbeds, glacial deposits, and mountain outcrops globally.
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