metamorphic

Quartzite with Mafic Intrusion (Gneiss/Schist Contact)

Metamorphic Quartzite (SiO2) with Amphibole/Biotite Schist

AI-generated identification · may be incorrect

Hardness: 7 (quartz section). Color: Milky white and dark charcoal grey. Luster: Vitreous to dull. Crystal structure: Granular metamorphic. Specific gravity: ~2.65-3.0.

Hardness: 7 (quartz section)
Color: Milky white and dark charcoal grey
Luster: Vitreous to dull

Identified June 15, 2026More metamorphic →

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Physical properties

Hardness: 7 (quartz section). Color: Milky white and dark charcoal grey. Luster: Vitreous to dull. Crystal structure: Granular metamorphic. Specific gravity: ~2.65-3.0.

Formation & geological history

Formed through regional metamorphism where sandstone (quartzite precursor) and igneous or clay-rich rock (dark precursor) were subjected to intense heat and pressure deep within the Earth's crust, often during mountain-building events.

Uses & applications

Primarily used as decorative landscape stone or as an educational geological specimen; quartz components are used in glass and electronics industries.

Geological facts

The sharp line between the white and dark sections represent a 'contact' zone, showing where two different types of rock fused together during metamorphic processes millions of years ago.

Field identification & locations

Identified by the inability for a steel knife to scratch the white portion (quartz) and the distinct color banding. Commonly found in glacial till or riverbeds in regions with ancient mountain roots.