Silliminate is one of three aluminosilicate polymorphs. It is an index mineral indicating high temperature but variable pressure. Natural sillimanite rocks cut into the required shape and size are used mainly in glass I, cermamic and various other industries.
Sillimanite is the best raw material for the manufacture of high alumina refractories or 55-60% alumina bricks.
Limestone is a carbonate sedimentary rock that is often composed of the skeletal fragments of marine organisms such as coral, foraminifera, and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal formsof calcium carbonate (CaCO3).
Limestones has numerous uses: as a building material, an essential component of concrete (Portland cement), as aggregate for the base of roads, as white pigment or filler in products such as toothpaste or paints, as a chemical feedstock for the production of lime, as a soil conditioner, or as a popular decorative addition to rock gardens.