mineral: hardness: cleavage/fracture: luster:
obsidian--------5-----------------------------fracture----vitreous
Halite----------2.5------------------cubic cleavage----vitreous
fluorite---------4---------------------------octahedral---vitreous
use the table to answer the question.
An unknown mineral specimen is not scratched by a penny and doesn't exhibit cleavage. The mineral is most likely to be?
a.obsidian
b.halite
c. fluorite