Diorite

Diorite is a coarse-grained intrusive igneous rock composed mainly of plagioclase feldspar and dark minerals such as hornblende. Its intermediate composition distinguishes it from lighter granite and darker gabbro.

Plagioclase: A group of feldspar minerals forming a continuous compositional series from albite to anorthite. Plagioclase is usually diorite’s dominant mineral and gives the rock much of its pale color.
Granite: A coarse-grained felsic intrusive igneous rock rich in quartz and alkali feldspar. Granite is more silica-rich and usually lighter than diorite.
Magma: Molten or partially molten rock beneath Earth’s surface, containing crystals and dissolved gases. Diorite forms when magma crystallizes below the surface.
Dimension stone: Natural stone quarried and cut to specified sizes for construction or decoration. Diorite can be quarried as durable stone for building and ornamental work.
Hornblende: A dark amphibole mineral common in igneous and metamorphic rocks. Hornblende is a frequent dark constituent that balances diorite’s light feldspar.
Gabbro: A coarse-grained mafic intrusive igneous rock dominated by calcium-rich plagioclase and pyroxene. Gabbro is darker and more magnesium- and iron-rich than diorite.
Fractional crystallization: The evolution of magma as early-forming crystals separate from the remaining melt. Crystal removal can shift magma toward the intermediate composition typical of diorite.
Road aggregate: Crushed mineral material used in road bases, asphalt, and concrete. Its hardness makes crushed diorite useful as aggregate in some construction projects.
Igneous rock: Rock formed when molten material cools and solidifies. Diorite belongs to this broad rock family, formed from magma.
Granodiorite: A coarse-grained intrusive rock with more plagioclase than alkali feldspar and substantial quartz. More quartz and a different feldspar balance separate granodiorite from diorite.

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AndesiteCompared with: Diorite is andesite’s plutonic compositional counterpart, crystallized underground.