metamorphic
Green Quartzite (River Stone)
Metamorphosed Quartz-rich Sandstone
Hardness: 7 (Mohs scale), Color: Dull to waxy green/grey, Luster: Vitreous to waxy, Crystal Structure: Microcrystalline, Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7
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Physical properties
Hardness: 7 (Mohs scale), Color: Dull to waxy green/grey, Luster: Vitreous to waxy, Crystal Structure: Microcrystalline, Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone under intense heat and pressure, often found as water-worn cobbles in riverbeds or glacial deposits. Typically Proterozoic to Paleozoic in age.
Uses & applications
Used in construction as crushed stone, road ballast, or decorative landscaping. Smooth river-worn specimens are popular for home decor and aquarium use.
Geological facts
Quartzite is so strong that it will break through the quartz grains rather than around them. It is one of the most durable rocks on Earth's surface.
Field identification & locations
Identified by its high hardness (scratches glass), lack of reaction to acid, and smooth, rounded water-worn texture. Often found in high-energy river environments or gravel pits.
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