Raw Black Tourmaline
Dimensions: approx 4" x 3" x 2.5"
Understanding the volcanic formation of pegmatite is basic to knowing how tourmaline is created, for most specimens of the colorful gem are found in veins that run through this kind of igneous rock. Pegmatite is characterized by being coarse-grained and often containing very large crystals. It occurs when magma undergoes a cooling process, but in contrast to other igneous rocks, pegmatite develops from aqueous solutions within the molten magma. These veins of hot liquids tend to be rich in certain earth elements such as silicon and iron. As the watery mix of elements cools and crystallizes, it forms the pegmatite rock, which can contain several different mineral crystals, one of which is tourmaline..