metamorphic
Granite Gneiss
Gneiss (High-grade Metamorphic Rock)
Hardness: 6-7 (Mohs scale); Color: Banded grey, white, and pinkish; Luster: Dull to vitreous; Structure: Foliated with distinct bands (gneissic banding); Specific Gravity: 2.6-2.9
- Hardness
- 6-7 (Mohs scale)
- Color
- Banded grey, white, and pinkish
- Luster
- Dull to vitreous
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (Mohs scale); Color: Banded grey, white, and pinkish; Luster: Dull to vitreous; Structure: Foliated with distinct bands (gneissic banding); Specific Gravity: 2.6-2.9
Formation & geological history
Formed through the high-grade regional metamorphism of pre-existing igneous rocks (like granite) or sedimentary rocks under intense heat and pressure deep within the Earth's crust.
Uses & applications
Commonly used as crushed stone for road construction, architectural stone for countertops or flooring, and as landscaping material or decorative river rocks.
Geological facts
Gneiss is one of the oldest rock types found on Earth, with some specimens from the Acasta Gneiss complex in Canada dating back over 4 billion years.
Field identification & locations
Identify by looking for 'salt and pepper' appearance with distinct mineral layering or banding. Commonly found in mountain cores or glacial till across North America and Europe.
More like this
