Top The exposed portion of the inner core exhibits the classic shell-like cleavage found in obsidian (very hard igneous rock).
(Top; exhibits; the classic shell-like cleavage found in obsidian (very hard igneous rock) (the classic shell-like cleavage; found; L:in obsidian (very hard igneous rock)
Top the classic shell-like cleavage
exhibits found
the classic shell-like cleavage found in obsidian (very hard igneous rock
L:in obsidian (very hard igneous rock