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Obsidian is formed from very rapidly cooling lava.
Obsidian
the parent rock of obsidian is magma, because it is made from quickly-cooling magma after a volcanic eruption.
Crystal size in these rock types is determined by their rate of cooling. Pegmatites have large crystals due to very slow cooling. Obsidian has microscopic crystals due to almost instantaneous cooling.
Glassy textured extrusive igneous rock, such as obsidian.
glassy
Glassy
Obsidian cooled very quickly. It's a vulcanic glass, meaning that the crystals are so small, they had virtually no time to form an orderly crystalline texture, and are basically placed randomly. Smaller grain size is associated with faster cooling.
Obsidian is formed from very rapidly cooling lava.
Granite is a rock, whereas obsidian is a type of glass formed by cooling lava.
Obsidian is volcanic glass, derived from the quick cooling of high silica lava.
Obsidian
Yes that is why it makes that glassy look to it.
obsidian
the parent rock of obsidian is magma, because it is made from quickly-cooling magma after a volcanic eruption.
Obsidian has a glossy texture is because of how it is formed. When it solidifies, it does not crystallize due to the lava cooling too quickly.
Igneoous rock is made from cooling of magma. Obsidian is a classic example of igneous rock.