metamorphic
River Stone (possibly Gneiss)
Metamorphic Gneiss
Hardness: 6-7 (Mohs scale); Color: gray with yellowish banding; Luster: dull to earthy; Crystal structure: crystalline but weathered; Cleavage: poor. This specimen shows a rounded, water-worn texture.
- Hardness
- 6-7 (Mohs scale)
- Color
- gray with yellowish banding
- Luster
- dull to earthy
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Physical properties
Hardness: 6-7 (Mohs scale); Color: gray with yellowish banding; Luster: dull to earthy; Crystal structure: crystalline but weathered; Cleavage: poor. This specimen shows a rounded, water-worn texture.
Formation & geological history
Formed under high pressure and temperature conditions deep within the Earth's crust, subsequently transported by water and rounded by river erosion over thousands of years.
Uses & applications
Commonly used as decorative garden stone, in landscaping, or as aggregate in construction projects. Small rounded stones like this are also popular for rock painting and craft projects.
Geological facts
Gneiss is one of the oldest types of rock on Earth, with some specimens dating back over 4 billion years. The banding is caused by the segregation of light and dark minerals during metamorphism.
Field identification & locations
Identify in the field by its rounded shape and visible banding or speckling. Commonly found in riverbeds, glacial deposits, and along coastlines. Collectors look for unique patterns or colors.
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