Obsidian is formed from very rapidly cooling lava.
obsidian
cool rapidly
Obsidian
In reference to the cooling of magma into rock, basalt is formed from rapid cooling.
Examples of igneous rocks are pumice, obsidian, basalt, and rhyolite.
obsidian
cool rapidly
Obsidian and Pāhoehoe lava
They cool to quickly for crystals to form.
Igneous rocks that cool quickly on the Earth's surface are called extrusive or volcanic rocks. Examples include basalt, obsidian, and pumice. These rocks have fine-grained textures due to their rapid cooling.
Obsidian
In reference to the cooling of magma into rock, basalt is formed from rapid cooling.
cool too quickly for mineral grains to form, resulting in a non-crystalline structure.
Examples of igneous rocks are pumice, obsidian, basalt, and rhyolite.
Obsidian is black glass formed by volcanoes.
because an obsidian rock has low silica
They are formed when either a sedimentary rock or a metamorphic rock are exposed to high heat and turn into magma and then cool quickly.