Obsidian Obsidian is an igneous rock that is very different than most other types.
(Obsidian Obsidian; is; an igneous rock that is very different than most other types) (an igneous rock; is; very different than most other types)
Obsidian Obsidian an igneous rock
is is
an igneous rock that is very different than most other types
very different than most other types