Sillimanite is a rare mineral that is mainly used in the manufacture of ceramic products and refractory materials. It is also known by other names, including Fibrolite, Bucholzite, and Kyanite-Sillimanite. Fibrolite, one of the synonyms of sillimanite, is derived from the Latin word "fibra" which means a thread or fiber. This is because the mineral often forms long, thin fibers that are commonly used in high-temperature insulation. Bucholzite is named after the German mineralogist, Christian Leopold von Buch, and is another name for the mineral. Kyanite-Sillimanite, on the other hand, is a combination of two minerals - kyanite and sillimanite - that are often found together in metamorphic rocks. This variant is often used in the manufacture of high-strength ceramics, abrasives, and cutting tools.