photos/090605_BobcatRidgeHike/

I_PegmatiteVein.JPG (270 Kb)

By Alan Silverstein, ajs@frii.com (page updated Fri Jun 25 21:37:31 MDT 2010)

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Now here was an interesting rock -- and I saw similar veins in other places. What happened is that hot magma forced its way into metamorphic rock, I would call it a slaty gneiss (but what do I know?) The pink intrusion, probably orthoclase feldspar, must have cooled relatively quickly because it's fine-grained. Note how it "baked" or otherwise altered the surrounding stone, darkening it.

I_PegmatiteVein.JPG