Obsidian is an extrusive felsic igneous rock.
Obsidian is a type of igneous rock that cools instantly after a volcano explosion. It is sometimes casually called volcanic glass.
Obsidian is classified as an an extrusive igneous rock; also as volcanic glass.
Obsidian is natural glass.
Obsidian
I'm thinking it's obsidian.
Granite is a rock, whereas obsidian is a type of glass formed by cooling lava.
obsidian
Obsidian
Obsidian
Obsidian is a volcanic glass which forms when a high silica melt solidifies quickly after eruption. Organic and chemical are terms used to classify sedimentary rock. Obsidian is an igneous rock type.
Obsidian is a naturally occurring volcanic form of glass.
obsidian? i think?
obsidian? i think?
Obsidian is an extremely sharp type of glass, so it is often used to make knives and scalpels.
Obsidian is an igneous rock.