Quartzite Pebbler

Physical Properties

Hardness: 7 on Mohs scale; Color: Tan to buttery yellow; Luster: Vitreous to dull/earthy when weathered; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.7

Formation & Geological History

Formed through the metamorphism of quartz sandstone under high heat and pressure, which causes the quartz grains to recrystallize and fuse together. The rounded shape suggests it was weathered and transported in a high-energy aquatic environment such as a river or shoreline.

Uses & Applications

Used primarily in construction as crushed stone or ballast. Often used as decorative landscaping stone or tumbled for lapidary use due to its hardness and ability to take a polish.

Geological Facts

Quartzite is so hard and chemically resistant that it often forms the caprock or ridges of mountain ranges because it resists erosion better than the rocks surrounding it. It is often harder than the steel of a masonry drill bit.

Field Identification & Locations

Identify in the field by its inability to be scratched by a steel knife (unlike limestone or marble) and its lack of reaction to acid. It typically breaks through the quartz grains rather than around them. Found globally in ancient mountain belts.

Identified on: 5/2/2026

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