Here's a breakdown of the different types:
By Mineral Composition:
* Felsic: Rich in silica (SiO2), potassium (K), sodium (Na), and aluminum (Al). They are typically light-colored and have low densities.
* Granite: Coarse-grained, often with visible crystals of quartz, feldspar, and mica.
* Rhyolite: Fine-grained, volcanic equivalent of granite.
* Obsidian: Glassy, volcanic rock formed when lava cools rapidly.
* Pumice: Light, porous rock formed by frothy lava.
* Intermediate: Have a mix of felsic and mafic minerals.
* Diorite: Coarse-grained, often gray or greenish with plagioclase feldspar and hornblende.
* Andesite: Fine-grained, volcanic equivalent of diorite.
* Mafic: Rich in magnesium (Mg) and iron (Fe). They are typically dark-colored and have higher densities.
* Gabbro: Coarse-grained, often dark green or black with plagioclase feldspar and pyroxene.
* Basalt: Fine-grained, volcanic equivalent of gabbro.
* Dolerite: Intermediate-grained, often with visible crystals of pyroxene.
* Ultramafic: Very high in magnesium and iron, with very little silica.
* Peridotite: Coarse-grained, often green or black with olivine and pyroxene.
* Komatiite: Very rare, ultramafic volcanic rock.
By Texture:
* Phaneritic: Coarse-grained, with visible crystals. Formed by slow cooling deep underground.
* Aphanitic: Fine-grained, with crystals too small to see with the naked eye. Formed by rapid cooling at the surface.
* Porphyritic: Has large crystals (phenocrysts) embedded in a fine-grained matrix. Formed by a combination of slow and rapid cooling.
* Glassy: Has no visible crystals, formed by very rapid cooling.
* Vesicular: Contains holes or cavities (vesicles) formed by escaping gases during cooling.
* Pyroclastic: Formed from fragments of volcanic rock and ash.
Examples of Igneous Rocks:
* Granite: Mountain peaks, countertops
* Rhyolite: Lava flows, volcanic domes
* Basalt: Ocean floor, lava flows
* Gabbro: Deep underground, ocean floor
* Obsidian: Knives, arrowheads
* Pumice: Bath products, lightweight building material
* Peridotite: Mantle rocks, gemstones
Note: There are many other types of igneous rocks, and some rocks can have characteristics of multiple categories. It's a complex and fascinating subject!
