Based on Composition:
* Basalt: This is the most common type of volcanic rock. It's dark-colored, fine-grained, and rich in magnesium and iron. Basalt flows easily and forms smooth, rope-like structures.
* Andesite: This type has a composition between basalt and rhyolite, meaning it's intermediate in silica content. It's typically gray to dark gray in color and contains both plagioclase feldspar and pyroxene.
* Rhyolite: Rich in silica, rhyolite is light-colored and often forms glassy or porphyritic textures. It's more viscous than basalt and tends to erupt explosively.
* Trachyte: A type of volcanic rock that is rich in sodium and potassium. It's generally light-colored, and often has a porphyritic texture with large crystals embedded in a fine-grained matrix.
* Komatiite: This is a rare and ancient type of volcanic rock, extremely rich in magnesium and iron. It's often black or dark green in color and has a very high melting point.
Based on Formation:
* Pahoehoe Lava: This type of lava flow is smooth and ropey, often characterized by glassy surfaces and rounded shapes. It forms from relatively fluid lava flows.
* Aa Lava: This type of lava flow is rough, blocky, and sharp, with jagged surfaces. It's formed from thicker, more viscous lava that cools and solidifies quickly.
* Pillow Lava: This type of lava forms underwater, where the rapidly cooling lava creates rounded, pillow-like shapes.
* Scoria: This is a type of volcanic rock that's full of holes, or vesicles, formed by escaping gas bubbles. It's typically red or black in color.
* Pumice: This is a very light and porous type of volcanic rock, often used as an abrasive or for landscaping. It's formed from frothy lava that cools quickly.
Other Notable Types:
* Tuff: This type of rock is formed from compacted volcanic ash, pumice, and other volcanic debris.
* Brecia: This is a volcanic rock that's composed of angular fragments of other volcanic rocks.
* Obsidian: This is a type of volcanic glass formed from rapidly cooling lava. It's often black or dark green in color and has a very smooth surface.
These are just some of the many types of lava rocks. The specific type of lava rock found in a particular location will depend on the composition of the magma from which it erupted and the conditions under which it cooled.
