What's on my mind.

02 November 2009

Ig/Met Pet question.

Callan's post on his new "granite" counter top reminded me of a post I meant to do while in Portland. I didn't have my camera so I had to wait until I got home, and I just drew a quick sketch of the gorgeous "granite" that adorned my bathroom at the Paramount. My petrology class was a while ago and I spend most of my time looking at the electrical properties of sedimentary rocks, so other than metamorphic I didn't get any further with this:

The biotite books in the groundmass (for lack of a better term) weren't that aligned (i.e. no preferred orientation), I was just lazy in Illustrator. The white space in the groundmass was mostly quartz with plag. The ground mass was medium to dark grey overall. The large feldspar clasts were between approximately .5"-1.25" (1 - 3cm, or nickel to Kennedy half-dollar); some had rings of biotite in them and/or inclusions of biotite, quartz, and rarely plag. A couple had rings of quartz inclusions - like an overgrowth of quartz followed by regrowth of feldspar; a few were almost complete overgrown by quartz.

So anyone know what it was?

"It's a terrible thing when gneiss is taken for granite"
-J.C. Pashin (and probably others)*

* Speaking of puns, check out Callan's Halloween costume