Tag Archives: biotite

Geopic of the week: Biotite crystal from Magnet Cove

image (5)

Igneous rocks are rare in Arkansas, making up about 0.1% of the surface area of the state.  Nonetheless, we find some interesting and unusual rocks and minerals within our igneous rocks.  The above picture is a pseudohexagonal, zoned, green biotite crystal collected from Magnet Cove, Arkansas just last week.  That’s a mouthful!

Magnet cove is a 100 million year old igneous intrusion, now exposed at the surface 12 miles east of Hot Springs, Arkansas.  In that little area, over 100 mineral species have been identified, including some that were first discovered there.  Students, researchers, and mineral enthusiasts come from all over to visit Magnet Cove, collect samples, and learn about this geologically fascinating place.

Advertisements