metamorphic
Quartzite
Metamorphic Quartzite (SiO2)
Hardness of 7 on the Mohs scale. Color is typically white, gray, or yellowish, often with sparkling crystal faces. Luster is vitreous to greasy. Crystal structure is trigonal/microcrystalline. Conchoidal fracture with no true cleavage. Specific gravity is approximately 2.65.
Identified More metamorphic →
Explore Quartzite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 7 on the Mohs scale. Color is typically white, gray, or yellowish, often with sparkling crystal faces. Luster is vitreous to greasy. Crystal structure is trigonal/microcrystalline. Conchoidal fracture with no true cleavage. Specific gravity is approximately 2.65.
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone or chert under high heat and tectonic pressure. The original quartz grains recrystallize and interlock to form an extremely dense and durable rock.
Uses & applications
Used in construction, road building, railroad ballast, manufacturing of silica brick, and sometimes as a decorative stone or countertop material.
Geological facts
Because quartz is one of the most chemically and physically resistant minerals on Earth, quartzite is extremely durable, highly resistant to weathering, and often forms prominent mountain ridges.
Field identification & locations
Can be identified in the field by its hardness (will easily scratch glass and cannot be scratched by a knife), lack of effervescence with acid, and the fused sugary-textured appearance of interlocking quartz grains.
More like this
