9 March 2011

A portrait of the feldspar as a young mineral

Posted by Callan Bentley

A few microscope photos for you, showing close-ups of feldspars in igneous dikes in the Crazy Mountains of Montana…

You’ve seen these rocks before, when I posted a few field photos from this area in August 2009. I took these images of feldspar phenocrysts in a hand sample (from a quartz latite dike) with my no-longer-brand-new Nikon microscope camera:

There’s some nice compositional zoning going on in some of these phenocrysts – reflecting the changing composition of the magma in which they nucleated and grew.