metamorphic

Gneiss with Quartz Veining

Gneiss (High-grade Metamorphic Rock)

AI-generated identification · may be incorrect

Hardness: 6-7 on Mohs scale; Color: Gray, white, and tan with rusty iron staining; Luster: Dull to vitreous (on quartz parts); Structure: Foliated (banded or layered) with coarse grains; Cleavage: None, irregular fracture.

Hardness: 6-7 on Mohs scale
Color: Gray, white, and tan with rusty iron staining
Luster: Dull to vitreous (on quartz parts)

Identified July 7, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed through high-grade regional metamorphism of igneous or sedimentary protoliths under intense heat and pressure. The visible white veins are quartz that precipitated from hydrothermal fluids in fractures.

Uses & applications

Used primarily as crushed stone for road construction and as decorative garden boulders. High-quality slabs are used for countertops and building facades.

Geological facts

Gneiss is one of the oldest types of rock on Earth, with some specimens in Canada dated to over 4 billion years old. The distinct banding is called 'gneissose banding'.

Field identification & locations

Identify by looking for distinct layers (foliation) and coarse mineral grains. Common in mountainous regions and areas with ancient continental shields. Check for 'salty-and-pepper' mineral appearance.