igneous
Diorite or Granodiorite Pebble
Intermediate Phaneritic Igneous Rock
Mohs hardness: 6-7. Color: Salt-and-pepper (white plagioclase with dark hornblende or biotite). Luster: Dull (weathered) to vitreous. Structure: Phaneritic (visible crystals).
- Hardness
- 6-7
- Luster
- Dull (weathered) to vitreous
Identified More igneous →
Explore Diorite or Granodiorite Pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Mohs hardness: 6-7. Color: Salt-and-pepper (white plagioclase with dark hornblende or biotite). Luster: Dull (weathered) to vitreous. Structure: Phaneritic (visible crystals).
Formation & geological history
Formed from the slow cooling of magma beneath the Earth's surface in continental crust environments, often near subduction zones. This specimen appears water-worn, likely from a river or beach.
Uses & applications
Larger deposits are used as crushed stone for construction, road base, or polished for countertops and architectural cladding.
Geological facts
Often referred to as 'salt and pepper' rock due to its contrasting mineral colors. It is chemically intermediate between acidic granite and basic gabbro.
Field identification & locations
Identify by the visible interlocking crystals of white/gray feldspar and black ferromagnesian minerals. Found in mountainous or glaciated regions worldwide.
