0
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.
Wiki User
∙ 12y ago
Add your answer:
Earn +20 pts
Smooth glassy rock that is formed when lava cools?
Obsidian
What types of rocks form with a great deal of heat and pressure?
obsidian
Can Obsidian turn into Granite?
Obsidian and Granite are both igneous rocks so unless the Obsidian rock goes back into the magma and cools slower it can possibly form into granite.
Some extrusive igneous rocks such as obsidian are glassy because they are what?
They cool to quickly for crystals to form.
What family is obsidian in?
Obsidian is part of the Granite family of igneous rocks.
What are very smooth rocks called?
obsidian obsidian
What is a name for volcanic glass?
One word for this is obsidian. Obsidian is a gorgeous hard stone, usually but not always black, and sometimes with iridescent, almost opalescent highlights. Tachylite is also a volcanic glass of basaltic composition.
Why do obsidian rocks look dark?
because an obsidian rock has low silica
What does obsidian mean in rocks and minerals?
Obsidian is black glass formed by volcanoes.
What type of rocks are pumice obsidian and granite?
Igneous rocks
What are rocks that have a glassy texture called?
Obsidian
What rocks do not weather or erode?
obsidian
