Obsidian is an igneous rock with a glassy appearance and minimal crystal growth.What accounts for this?
A)Obsidian is an intrusive igneous rock that cooled slowly beneath Earth's surface,result in little crystal growth.
B)Obsidian is an extrusive igneous rock that cooled slowly on Earth surface,resulting in little crystal growth.
C)Obsidian is an extrusive igneous rock that cooled very slowly on Earth surface,resulting in little crystal growth.
D)Obsidian is an intrusive igneous rock that cooled rapidly beneath Earth's surface,result in little crystal growth.

Question

Quizplus · Accepted Answer

Obsidian is formed from lava that cools very quickly on the Earth's surface, which does not allow for much crystal growth. As a result, obsidian has a glassy appearance and minimal crystal growth. Option A and D are incorrect because they refer to obsidian as an intrusive rock, which is incorrect. Option C is incorrect because obsidian is formed from lava that cools very quickly, not slowly.

Obsidian Is an Igneous Rock with a Glassy Appearance and Minimal