Where is pegmatite mined in Western Australia?
Wow! Let me try…… 1. Pegmatite is a very coarse-grained igneous rock that has a grain size of 20 mm or more; such rocks are referred to as pegmatitic. 2. Most pegmatites are composed of quartz, feldspar and mica; in essence a “granite”. 3. Crystal size is the most striking feature of pegmatite, with crystals usually over 50mm in size. However, individual crystals over 10 meters across have been found, and the world’s largest crystal was found within a pegmatite. 4. Metamorphism and magmatism both contribute toward the conditions necessary for pegmatite genesis. 5. Pegmatites are important because they often contain rare earth minerals and gemstones, such as aquamarine, tourmaline, topaz, fluorite, and apatite, often along with tin and tungsten minerals, among others. For example, beautiful crystals of aquamarines and topaz can be found in pegmatites in the mountains of Colorado and Idaho. 6. Pegmatites are the primary source of lithium either as spodumene, lithiophyllite or usually
