Yellow Quartzite

Physical Properties

Hardness: 7 on Mohs scale; Color: Yellowish-tan, honey, amber; Luster: Vitreous to waxy when water-worn; Crystal structure: Trigonal (as quartz grains); Cleavage: None; Specific Gravity: 2.6 – 2.7.

Formation & Geological History

Formed through the regional metamorphism of quartz-rich sandstone. High heat and pressure caused the original quartz sand grains to recrystallize and fuse together into a dense, hard rock. The yellow color is primarily due to the presence of limonite or other iron oxide impurities trapped during formation.

Uses & Applications

Used as decorative stone in landscaping, crushed stone for construction projects, and occasionally as a semi-precious gemstone when polished into 'river stones' or cabochons. Historically used for making tools due to its hardness.

Geological Facts

Quartzite is so tough that it often outlasts the surrounding rock layers, frequently appearing as the capping rock on hills and ridges. It is often confused with marble, but can be distinguished because quartzite is much harder and will not react (fizz) with acid.

Field Identification & Locations

Identify in the field by its grainy, sugary texture and inability to be scratched by a steel knife. It is commonly found in mountain ranges and riverbeds where old metamorphic basement rocks are exposed. Collectors look for pieces with high translucency.

Identified on: 4/25/2026

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