GeologyRocksWhat is this rock?
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AwesomeHartman
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Apologies for the late
Thu, 05/22/2014 - 16:33Apologies for the late reply. They definitely have the color/shape of hornblende. I can't find any rocks with a large mass of elongated hornblende chrystals online that look quite like this one. Do you think it is just a granite porphyry?
@PBGeo The interior looks the same as the exterior. I'll get a better picture when it stops raining outside.
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What is this rock?
Submitted by AwesomeHartman on Sun, 05/11/2014 - 22:59.Hi rockstars,
A strange rock caught my eye while I was prowling the Lake Isabella lakebed. It was found in a boulder wash, so it likely originated from the Sierra Nevada mountains nearby. It consists of somewhat pearly or silky black, elongated crystals in a white/orange/pink matrix (it varies across the rock). It caught my eye because unlike granite or diorite, these crystals have a distinct shape. I have shown it to a few people, including a geologist, and they have speculated on it being peridotite, diabase, or amphibolite. I'm leaning toward amphibolite, since it's not greenish, and the colors are opposite of diabase, but I'd like to hear some ideas from you guys. I collected several other specimens, the largest two of which I photographed and uploaded on imgur:
http://i.imgur.com/y4rj639.jpg?1
http://i.imgur.com/z2FuX8S.jpg?1
Thanks