igneous
Granite Pebble
Granite (Felsic Plutonic Rock)
Hardness: 6-7 on Mohs scale; Color: Light gray or cream with speckled black/pink; Luster: Crystalline-dull; Structure: Phaneritic (visible crystals of quartz, feldspar, and mica).
- Hardness
- 6-7 on Mohs scale
- Color
- Light gray or cream with speckled black/pink
- Luster
- Crystalline-dull
Identified More igneous →
Explore Granite Pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 on Mohs scale; Color: Light gray or cream with speckled black/pink; Luster: Crystalline-dull; Structure: Phaneritic (visible crystals of quartz, feldspar, and mica).
Formation & geological history
Formed from the slow cooling of silica-rich magma deep underground, likely during the Caledonian orogeny (approx. 400 million years ago) given the regional geology of SE Ireland.
Uses & applications
Used extensively in construction as aggregate, dimension stone for buildings, and countertops; smaller pebbles are popular for landscaping and aquarium decor.
Geological facts
The regional coordinates place this near the Wicklow/Wexford border in Ireland, home to the Leinster Granite pluton, the largest of its kind in the British Isles. This pebble has been rounded by glacial or fluvial erosion.
Field identification & locations
Identify by its salt-and-pepper appearance and the way it resists scratching. Common in glacial till and on beaches across Southeast Ireland.
