metamorphic
Quartzite Pebble
Metamorphosed Quartz Sandstone (SiO2)
Hardness: 7 (Mohs), Color: creamy tan with grayish inclusions, Luster: dull to vitreous, Crystal structure: Trigonal (microcrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 (Mohs), Color: creamy tan with grayish inclusions, Luster: dull to vitreous, Crystal structure: Trigonal (microcrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Formation & geological history
Formed through the regional metamorphism of quartz-rich sandstone. High heat and pressure Recrystallize quartz grains into a dense, interlocking matrix. This specimen shows signs of fluvial erosion (rounded by water).
Uses & applications
Commonly used as crushed stone in road construction, railroad ballast, and decorative landscaping. High-purity quartzite is used to produce glass and ferrosilicon.
Geological facts
Quartzite is so tough that it often outlasts the surrounding rocks during weathering, frequently standing out as ridges or hills. It is one of the hardest common building materials.
Field identification & locations
Identify by its ability to scratch glass and its grainy, sugary texture under a lens. Common in riverbeds and glacial deposits. For collectors, look for smoothness and color uniformity.
More like this
