Yellow Quartzite (Iron-Stained Quartz)

Physical Properties

Hardness: 7 on Mohs scale. Color: Yellow to brownish-orange due to limonite/hematite staining. Luster: Vitreous to dull. Crystal structure: Trigonal (microcrystalline/granular). Cleavage: None (conchoidal fracture). Specific gravity: 2.65.

Formation & Geological History

Formed through the metamorphism of quartz sandstone. Under high heat and pressure, quartz grains recrystallize and fuse together. The yellow color comes from iron oxides leaching into the stone over geological time.

Uses & Applications

Used as decorative stone in landscaping, crushed for road construction, as a source of silica for glass making, and occasionally tumbled for low-end jewelry or aquarium decor.

Geological Facts

Quartzite is so tough that it often outlasts the surrounding rock in weathering processes, resulting in ridges or hills called monadnocks. It is more durable and chemical-resistant than marble.

Field Identification & Locations

Identify by its hardness (it will easily scratch glass) and its sugary, granular texture that looks like sand grains fused into a solid mass. Commonly found in riverbeds and glacial deposits. For collectors, look for pieces with high translucency.

Identified on: 4/17/2026

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