c Study Mount Elephant‎ > ‎Geology‎ > ‎rock samples‎ > ‎

Crystal forms

(update 6/5/17)
As the lava cools and decompresses on its trip up through the crust some crystals may form.

Amazing crystal of olivine found by a student on Mount Shadwell in May 2017.

This appears to be a single fractured crystal and not the more common multiple small crystals.



















The best known crystal from basalt is green olivine. This is first to crystallize out as the lava cools. The process is similar to various salts crystallizing as water dries in a salty lake.
In lava the olivine is the first to crystallize as it cools slowly and quartz is about the last.














Appears to be a mix of red and green olivine.


















Appears to be red olivine and pyroxene.


















Appears to be a black olivine.



















These are possibly quartz crystals which formed as it cooled.


















Possibly "pyroxene" related to olivine.


















Rounded edges, heavy, small crystal structure. Several samples.


















Quartz geode? long crystals inside.


















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Quartz crystals inside a bomb?


















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