David Corrigan

David Corrigan

Posted on 08/15/2013


Photo taken on August 10, 2011


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Olivine crystals in basalt, Hilo, Hawaii

Olivine crystals in basalt, Hilo, Hawaii
The basaltic flows around Hilo are quite rich in olivine phenocrysts. Some of these get liberated by erosion and concentrate with wave action, forming green beaches (especially on the south shore of Big Island).

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the longhairbroad
the longhairbroad
Wow. I did not know enough could weather out to cover a beach!
4 years ago.
David Corrigan
David Corrigan
Some of the volcanic flows on Big Island are quite rich in olivine. When the crystals get liberated over time, they get concentrated by waves because of their high density... a bit like gold in a pan after a bit of shaking. These green beaches are a popular tourist attraction in Hawaii, as well as pure black sand beaches made out of volcanic glass beads.
4 years ago.
the longhairbroad
the longhairbroad
I remember reading about the black sand beaches years ago and wondering what material they were. Thanks for answering my question. I love geology.
Wouldn't it be cool to have a meteorite with some olivine in it?
4 years ago.