Day #25 Deskcrop: Black Sand

It seems to be “Sand Week” in the geoblogosphere*. Ian Stimpson has been featuring deskcrops of local sandstones, and Brian Romans has reviewed Michael Welland‘s new book Sand: The Neverending Story (which just went into my Amazon shopping cart) and conducted a Q&A with Michael over at Clastic Detritus (how apropos). Callan Bentley gets to host the roving virtual book tour next week, followed by David Williams and Andrew Alden. (Kansans don’t read books, I guess, or maybe it’s just that sand is still a bit of a sore subject here. Anyhow, I know when I’ve been told to pound sand.)

So for this week’s deskcrop series, let’s see how much the experts know about their sand. Four distinctive sands on Monday thru Thursday, and then an evil stumper on Friday. If you’re up to the challenge, comment on what you think the composition of the sand is and where it’s from. We’ll find out who knows their sand… ;-)

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Black Sand (Macro)

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Black Sand (15mm microscopic)

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Black Sand (microscopic closeup)

*Although this post has Monday’s date on it, I’m actually posting it and the following four “sand series” posts late Thursday evening.

[Update: As many of you were able to surmise this is indeed black sand from a Hawaiian beach. The sand is dominated by coarse, angular, well-sorted sand composed primarily of basaltic glass, with minor olivine. The locality of this sample is the Punalu'u Black Sand Beach, on the south shore of the Big Island of Hawaii.]