Yellow Quartzite (Iron-stained Quartz)

Physical Properties

Hardness: 7 (Mohs scale). Color: Translucent golden-yellow to honey-brown. Luster: Vitreous to waxy when weathered. Crystal structure: Trigonal/Hexagonal (microcrystalline in this form). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Formation & Geological History

Formed from the metamorphism of quartz-rich sandstone under intense heat and pressure. The yellow coloration is typically a secondary iron-oxide stain (limonite or goethite) that has permeated the grain boundaries of the stone over geological time.

Uses & Applications

Used primarily as decorative landscaping stone, in aggregate for construction, and as an ornamental stone for lapidary work such as tumbling and cabochon cutting.

Geological Facts

Quartzite is frequently harder than the steel of a pocketknife. It is so durable that it often remains as pebbles in riverbeds long after softer rocks have eroded away. The staining suggests this piece spent significant time in an oxygen-rich, moisture-heavy environment.

Field Identification & Locations

Identify in the field by its inability to be scratched by steel and its grainy, 'sugary' texture on fresh breaks. It is commonly found in glacial till, riverbeds, and mountainous regions like the Appalachians or the Rockies.

Identified on: 4/25/2026

Mode: Standard