tag:blogger.com,1999:blog-5211670216140060946.post4478376209765676515..comments2024-03-17T18:37:36.377-07:00Comments on Geotripper: A Mystery Photo for a Tuesday (and a bonus mystery photo)Garry Hayeshttp://www.blogger.com/profile/00531226195147986457noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-5211670216140060946.post-62182036613136839722011-08-24T19:41:20.222-07:002011-08-24T19:41:20.222-07:00Well of course the top one is obsidian and the sec...Well of course the top one is obsidian and the second is also volcanic but not being a geologist I lump such things together as pumice or tuff. These are found together in the obsidian dome and craters in the Eastern Sierra near my summer home.Martha Zhttps://www.blogger.com/profile/15797951661712327698noreply@blogger.comtag:blogger.com,1999:blog-5211670216140060946.post-17344446455974235972011-08-24T13:13:58.825-07:002011-08-24T13:13:58.825-07:00Glassy luster on 1st definitely looks like obsidia...Glassy luster on 1st definitely looks like obsidian. 2nd looks like vesicular basalt- not quite bubbly enough to call it scoria- plus some secondary minerals, maybe tufa, or just some dirty calcite from weathering.Lockwoodhttps://www.blogger.com/profile/05960762797349483760noreply@blogger.comtag:blogger.com,1999:blog-5211670216140060946.post-2479925153361767832011-08-24T09:25:55.091-07:002011-08-24T09:25:55.091-07:00I'm a total non-geologist, but agree with the ...I'm a total non-geologist, but agree with the above that these look volcanic, 1st looks obsidian-like, 2nd looks pumice-like, both cooled very quickly. And that, dear people, is about the end of my geologic-database. I WILL be back to check out the answers! =)biobabblerhttps://www.blogger.com/profile/15081382623906668057noreply@blogger.comtag:blogger.com,1999:blog-5211670216140060946.post-33800124063493219092011-08-24T06:20:24.599-07:002011-08-24T06:20:24.599-07:00Looks like the obsidian and tuffa I've seen fr...Looks like the obsidian and tuffa I've seen from the Salton Sea area.Gaelynhttps://www.blogger.com/profile/05784162697113288888noreply@blogger.comtag:blogger.com,1999:blog-5211670216140060946.post-73839159705955292422011-08-23T20:16:10.151-07:002011-08-23T20:16:10.151-07:00Since my intuition says Obsidian, and the lower on...Since my intuition says Obsidian, and the lower one looks kind of tuffaceous, I'm going to posit that the above is either devitrified obsidian, or secondarily deposited silica. The lower ones look pretty heavily altered, tooMatt Kuchtahttps://www.blogger.com/profile/18168846490598155683noreply@blogger.com