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Some extrusive igneous rocks such as obsidian are glassy because they are what?
Wiki User
∙ 8y ago
They cool to quickly for crystals to form.
June Douglas
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Some extrusive igneous rocks such as obsidian are glassy because they?
cool rapidly
How some extrusive igneous rocks such as obsidian are glassy is because they?
Cool rapidly
Which igneous rocks would be formed by the fastest cooling of lava?
Glassy textured extrusive igneous rock, such as obsidian.
What is an extrusive igneous rock that is actually glass?
One type of glassy igneous rock is obsidian, which is black and glass-like. Any type of igneous rock that is glassy would be a extrusive rock, which means it was formed outside the earths crust and cooled quickly, making for a fine grain and small crystals. hope this helps
Where does obsidian rock cools down?
Obsidian is an glassy, extrusive, igneous rock that is found in areas that have experienced rhyolitic eruptions. Obsidian is formed when the rhyolitic lava comes into contact with water. This quick-cooling results in the glassy texture of obsidian.
What is a glassy grained extrusive rock?
Obsidian.
A glassy fine grained extrusive rock?
Obsidian
What is a glassy fine-graind extrusive rock?
obsidian
Some igneous rocks such as obsidian are glassy because they?
cool rapidly
What kind of igneous rock is obsidian?
Obsidian is an igneous rock. However it differs from other rocks because it contains no minerals. It consists of natural glass, which is not a mineral because it has no crystal structure.Answers from McDougal Littell, Earth Science book
Smooth glassy rock?
Obsidian: Its texture is glassy. Obsidian is extrusive or volcanic, because the instantaneous cooling that produces such rocks is a surface phenomenon. Obsidian is amorphous, so, unlike true rocks, it is not composed of minerals.
Smooth glassy rock that is formed when lava cools?
Obsidian
