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Which pair of rocks could each be composed of only one mineral?
1.- dunite and rock salt
2.- peridotite and rock gypsum
3.- dolomite and obsidian
4.- marble and schist
2 Answers
- Anonymous1 decade agoFavorite Answer
None of them are perfect.
(1) Dunite is mostly olivine (90%), rock salt is halite.
Source(s): Geologist - Mark SLv 41 decade ago
I think 3 is probably closest, as dolomite can be exclusively calcium magnesium carbonate and obsidian is volcanic glass (silica). But obsidian is dark, typically black, because of many impurities, and strictly speaking obsidian is NOT a mineral because it is non-crystalline (as glass).
