Here's a breakdown:
* Igneous rocks are formed from the cooling and solidification of magma (molten rock) or lava.
* Phaneritic refers to the texture of the rock, meaning it has large, visible crystals that are easily recognizable with the naked eye. This occurs when the magma cools slowly, giving the mineral crystals ample time to grow.
Some common examples of phaneritic igneous rocks with blocky crystals include:
* Granite: A light-colored, coarse-grained rock with visible crystals of quartz, feldspar, and mica.
* Diorite: A medium-grained, dark-colored rock with crystals of plagioclase feldspar, hornblende, and sometimes biotite mica.
* Gabbro: A dark-colored, coarse-grained rock with crystals of plagioclase feldspar and pyroxene.
* Peridotite: A dark-colored, coarse-grained rock with crystals of olivine and pyroxene.
Note: While blocky shapes are common in phaneritic igneous rocks, other crystal shapes can also occur, depending on the mineral composition and cooling conditions.
It's important to remember that not all rocks with blocky crystals are igneous. Some metamorphic rocks can also have visible, blocky crystals, but these are formed through the transformation of existing rocks under heat and pressure.
