metamorphic
Quartz-rich metamorphic pebble
Milky quartz with possible feldspar and mica; likely quartzite or quartz-veined metamorphic rock
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; white, cream, gray, and tan coloration with vitreous to dull luster. Massive, interlocking granular texture; cleavage is absent or poorly developed, and quartz specific gravity is about 2.65.
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Physical properties
Hardness about 6.5–7 Mohs; white, cream, gray, and tan coloration with vitreous to dull luster. Massive, interlocking granular texture; cleavage is absent or poorly developed, and quartz specific gravity is about 2.65.
Formation & geological history
Likely formed when quartz-rich sediment or a silica-bearing vein recrystallized during metamorphism; the rounded shape indicates later stream or glacial transport. Exact geological age cannot be determined from the photograph.
Uses & applications
Used chiefly as a lapidary, teaching, and collectible specimen; quartzite is also used as aggregate, building stone, and decorative rock. This small ordinary piece has little commercial value.
Geological facts
The translucent white areas are consistent with milky quartz, whose cloudiness commonly comes from microscopic fluid inclusions or fractures. Brown staining is probably iron oxide, while darker patches may be mica or other host minerals.
Field identification & locations
Identify by its very hard, non-cleaving quartz grains and inability to scratch with a steel knife; vinegar will not fizz. Common in quartz veins, metamorphic terrains, stream gravels, and glacial deposits.
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