Quartzite (Gold/Yellow)

Physical Properties

Hardness: 7 on Mohs scale; Color: Yellowish-tan to gold; Luster: Vitreous to greasy; Crystal Structure: Trigonal (granular texture); 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, causing recrystallization of quartz grains. Geological age varies by deposit, typically found in Proterozoic or Paleozoic formations.

Uses & Applications

Used in construction as crushed stone or decorative building stone, in high-end glass manufacturing, and as a semi-precious stone for landscape gardening and lapidary work.

Geological Facts

Quartzite is so hard that it can scratch steel and glass. It is often confused with marble, but unlike marble, it will not react or fizz when exposed to acid.

Field Identification & Locations

Identify in the field by its hardness (scratches glass), grainy texture that resembles sandpaper but feels smooth/glassy on fresh breaks, and absence of reaction to vinegar. Commonly found in mountain ranges and eroded riverbeds.

Identified on: 4/17/2026

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