metamorphic

Yellow Quartzite Pebble

Quartzite (primarily Silicon Dioxide - SiO2)

AI-generated identification · may be incorrect

Hardness: 7 (Mohs scale), Color: Yellow-tan, Luster: Vitreous to dull (waxy), Crystal Structure: Trigonal/Hexagonal (microcrystalline), Cleavage: Indistinct/Conchoidal fracture, Specific Gravity: 2.6-2.65

Identified April 13, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed through the metamorphism of quartz-rich sandstone. High heat and pressure Recrystallize quartz grains into a dense, interlocking mosaic of crystals. Often found as rounded river pebbles due to water erosion.

Uses & applications

Used as decorative landscaping stones, ballast in construction, and when crushed, as a source for glass manufacturing. Smooth pebbles like this are popular in aquarium decor and rock tumbling.

Geological facts

Quartzite is so tough that it often outlasts the surrounding rocks; it is more durable than many other common minerals and can actually scratch steel. Its yellow color often comes from iron oxide impurities trapped during metamorphism.

Field identification & locations

Identify by its extreme hardness (cannot be scratched by a knife) and its grainy, sugary texture under a hand lens. Commonly found in riverbeds, glacial deposits, and mountain ranges. It is an indicator of previous intense tectonic activity.