metamorphic

Likely weathered quartzite or quartz-rich sandstone

Quartzite; predominantly microcrystalline quartz (SiO₂), possibly retaining sandstone texture

AI-generated identification · may be incorrect

Gray-tan, fine-grained, dull to subtly sparkling surface with irregular fractures and no obvious cleavage; quartz hardness is about Mohs 7, with generally high durability and specific gravity near 2.65.

Identified September 5, 2026More metamorphic →

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Physical properties

Formation & geological history

Likely formed when quartz-rich sandstone was compacted and recrystallized during metamorphism, commonly during mountain-building; its exact geological age cannot be determined from the photograph.

Uses & applications

Ordinary pieces have little commercial value, while quartzite is used as crushed stone, aggregate, landscaping rock, and durable building or paving material.

Geological facts

Quartzite commonly breaks across individual grains rather than around them and is typically harder than ordinary sandstone; this specimen may also be a strongly cemented sandstone rather than true quartzite.

Field identification & locations

Test with a steel knife: it should resist scratching; quartzite may scratch glass, whereas sandstone commonly powders or scratches more easily. Common in metamorphic belts worldwide, including the Appalachians, Rocky Mountains, India, and Scandinavia.