Sold Out

gneiss - orthogneiss, Grenville age, from near St. Jerome, Quebec - hand/display specimen

$ 12.50

Back in stock soon. Inquire.

Orthogneiss is formed by the metamorphism of igneous rocks. This gneiss is from a one to two-billion year old orogenic crustal relic of of mid-late Mesoproterozoic age in the Quebec Laurentians near St. Jerome. The absence of multiple metamorphic features suggests that the age is near the younger limit. Pink orthoclase imparts its color to this gneiss. The foliated black mineral is biotite.

A student should identify this as a gneiss because of the banding, or foliation, that is present. The color is something we do not see in U.S. west coast gneisses. Those are generally black and white. An interesting rock type, with an age only seen in very old crust.




Select a specimen: When more than one specimen is shown, you can select a particular specimen by telling us what is in the photo with it, a black and silver pen, a black mechanical pencil, a blue and silver pen, or one of those plus some number of coins, or you can let us make the selection.

Making multiple purchases? Click on the "combine shipping" button in the shopping cart. We'll send an invoice with combined shipping. A link in that invoice will bring you back to checkout, no hassle.

Shipping: By Priority Mail. Click > here < for shipping rates. See comment at Note! Use back button to return to this page.