16 November 2011

Labradorite is mineral du jour

Posted by Callan

Other members of the geoblogosphere have been posting brief image-heavy missives on labradorite over the past 24 hours. Collectively, they remind me that I’ve got a backlog of photos from the Adirondacks of upstate New York to share. Here are a few scans of cut and polished cobbles of the anorthosite from the Adirondack Massif, including bluish crystals of labradorite.

What I find most lovely about these, though, is not the abundant plagioclase, but the “necklaces” of garnet which ring the pyroxenes. Here’s the other half of the sample imaged above:

And a close-up of the garnet reaction rims mantling the greenish pyroxenes;

One more: a weathered sample, tinged throughout with rust: