Monday, October 25, 2010

Reminder: Accretionary Wedge!

Call for Posts!

Just a reminder - the October "Accretionary Wedge" is being hosted here at RAASP. We may be small, but we've cleared a whole blog entry just for this.

You can leave a comment on this thread, the original post on this blog, or the Accretionary Wedge site.

If you don't have a blog, but still want to participate - send an email to me (find it via the profile page). Include your name, a brief description, plus a photo (keep the file size reasonable, please). I'll add it to the mix.

Here's a preview:

Many geologists have access to a rock saw now and then. The desire to cut rocks into useful/interesting shapes can have quite a pull. I have no idea where the rock came from (save for the UW Geology Museum Giftshop, or exactly what it is - it's mass is 776.9 g. An estimate for volume put it at 283.1 cm3, which gives a specific gravity of about 2.74. It scratches glass, but not quartz.

I think it has some quartz mixed in, but I'm not sure about the green stuff. It kind of matches some of the descriptions of Scapolite group minerals, but the color seems a little weird a few flecks do fluoresce a pale yellow-white. It's got a generally metamorphic vibe/fabric, which is probably why it's causing me trouble. And yes, "vibe" should be a diagnostic category for rocks and minerals - we can put that into the next edition of Hurlbut & Klein.


  1. At last:

    A simple yet tough topic!