2.7" Brookite Crystal Cluster on Matrix - Pakistan
This specimen displays two undammaged brookite crystals that were collected from Baluchistan, Pakistan. They appear to have formed and then been covered by a natural mineral deposit. Work has been done to expose them from this deposit, though it appears that there are two more unexposed crystals in this cluster.
Brookite is one of the five forms of titanium dioxide found in nature and forms almost always in association with another mineral, frequently with quartz. This small unique crystal is typically microscopic, though is known to grow larger in some locations. Pakistan tends to be the location where some of the most beautiful and vibrant brookite specimens come out of, for the crystals are a brown-orange translucent color, forming flat chip like projections out of matrix. In some rare cases, just the sim card-like crystals have been found intact, separated from a matrix on their own, these specimens are called "floaters".
Silicon Dioxide, also know as SiO2 or Quartz, is the second most abundant mineral in the Earth's crust. Quartz crystals generally grow in silica-rich, hot watery solutions called hydrothermal environments, at temperatures between 100°C and 450°C, and usually under very high pressure. Quartz veins are formed when open fissures are filled with hot water during the closing stages of mountains forming, and can be hundreds of millions of years old.