metamorphic
Likely quartz-rich metamorphic rock (quartzite or milky quartz)
Quartzite; predominantly quartz (SiO₂), possibly with feldspar and iron-oxide staining
AI-generated identification · may be incorrectPale gray-white, granular to massive, with a dull-to-glassy luster; quartz hardness is Mohs 7, with no cleavage and irregular fracture. The image suggests a weathered, fine- to medium-grained specimen, but texture is insufficient for certain identification.
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Physical properties
Pale gray-white, granular to massive, with a dull-to-glassy luster; quartz hardness is Mohs 7, with no cleavage and irregular fracture. The image suggests a weathered, fine- to medium-grained specimen, but texture is insufficient for certain identification.
Formation & geological history
Quartzite forms when quartz-rich sandstone is recrystallized during regional metamorphism, typically during mountain building; its age depends on the source sandstone and metamorphic event. If massive rather than granular, it could instead be vein quartz.
Uses & applications
Used as crushed aggregate, road stone, refractory material, and dimension stone; attractive pieces may be used decoratively or as lapidary material. This specimen appears more suitable for collecting than jewelry.
Geological facts
Quartzite commonly preserves little of the original sandstone texture because interlocking quartz grains fuse during metamorphism. A steel scratch test helps distinguish it from softer white rocks such as marble or calcite.
Field identification & locations
Common in metamorphic mountain belts worldwide, including the Appalachians, Rocky Mountains, Alps, and Precambrian shields. Look for a sugary texture and resistance to scratching; dilute acid should not fizz unless carbonate minerals are present.
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