Thursday, July 24, 2014

Geo 730: July 24, Day 570: Stilbite Closeup

A closer view of yesterday's vesicular basalt. This shot is close enough that in crops of the full-size image, one can make out the individual blades. Compare the shape of the circled bits below to the diagrams and photos at this site. I will say, I take issue with their claim that "single individual crystals are very uncommon." Larger crystals that are not in clusters are not common, but smaller crystals, easily identified with the naked eye or with a hand lens, are pretty common, in my experience, in the Western Cascades, where these photos were taken and in Oregon's Coast Range.
(Crop from the upper left edge of photo) These two aren't in very sharp focus, especially on the right, but the "house outline" shape is pretty clear to me. On the left, the axis is pointing nearly straight up; I'll call it 12:30. On the right, it points to about 10:00.
(Crop from about a third of the way down from my index finger and a bit to the right) This one is the best I could find; it points to about 11:00.

Photo unmodified. June 19, 2014. FlashEarth location.

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