igneous
Diorite (or Granite / Granodiorite)
Plutonic Igneous Rock (Intermediate to Felsic)
Hardness: 6-7 on Mohs scale. Color: Salt-and-pepper appearance with mottled white/grey plagioclase feldspar and dark amphibole (hornblende) or biotite mica. Luster: Vitreous to dull. Texture: Phaneritic (coarse-grained, visible interlocking crystals).
- Hardness
- 6-7 on Mohs scale
- Luster
- Vitreous to dull
Identified More igneous →
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Salt-and-pepper appearance with mottled white/grey plagioclase feldspar and dark amphibole (hornblende) or biotite mica. Luster: Vitreous to dull. Texture: Phaneritic (coarse-grained, visible interlocking crystals).
Formation & geological history
Formed through the slow cooling and crystallization of magma deep beneath the Earth's surface in subduction zones and volcanic arcs.
Uses & applications
Used as a decorative dimension stone, aggregate in construction, curbing, and historically carved into durable statues and inscriptions.
Geological facts
Diorite is extremely hard and durable; ancient Egyptians used diorite spheres as hammers to carve granite monuments and Obelisks.
Field identification & locations
Identified by its distinctive phaneritic 'salt-and-pepper' texture featuring roughly equal mixtures of dark ferromagnesian minerals and light feldspar. Found in volcanic arc roots such as the Andes, Cascades, and European Alps.
