Larvikite is a black igneous rock made up entirely of feldspar (with small chemical composition changes) that crystallizes in the form of large masses. Within the feldspar itself, there are small silver-blueish shimmering crystals that give Larvikite its notoriety and fame. This eye catching “flash” is commonly referred to as the “Schiller Effect” and is believed to have been caused by Ternary Feldspar (a fancy name for feldspar that is rich in potassium, sodium, and calcium). Larvikite is believed to have formed over 298 million years ago, at an estimated depth of 18 miles below Earth’s surface (an astounding feat considering large deposits of this mineral are now breaching continental Norway). The name of this mineral comes from the local town of its original discovery; Larvik, Norway. Since then a few deposits have been discovered throughout the world, with the other major source coming out of Thunder Bay, Ontario, Canada.
