orthogneiss - mid to late Proterozoic, St. Jerome, Quebec - hand specimen

orthogneiss - Grenville Age mid to late Mesoproterozoic ~1 billion years old St. Jerome, Quebec, Canada This Proterozoic red gneiss is derived from granitic rocks that were deeply buried and metamorphosed. When derived from granitic rocks, a gneiss is called an orthogneiss. In this specimen, the pink is orthoclase feldspar, the white mineral is quartz, and the black mineral is biotite. Gneiss can also be derived from sedimentary rocks, and is often named for a mineral constituent of that gneiss, eg: garnet gneiss or biotite gneiss. Making multiple purchases? Click on the "combine shipping" button in the shopping cart. We'll send an invoice with combined shipping. It may not be instantaneous, since a human has to take a look and we might be out in the field during the day. A link in that invoice will bring you back to checkout, no hassle. Shipping: By Priority Mail or USPS Ground Advantage, whichever is cheaper, unless we find a better rate. Click > here < for shipping rates. See comment at Note! Use back button to return to this page.