Hypersthene is a common rock-forming inosilicate mineral belonging to the group of orthorhombic pyroxenes. Its chemical formula is (Mg, Fe) SiO3. It is found in igneous rocks and some metamorphic rocks as well as in stony and ferrous meteorites. Many references have formally abandoned this term, preferring to classify this mineral as enstatite or ferrosilite. It forms a series of solid solutions with the minerals enstatite and ferrosilite, being a member halfway between the two. Pure enstatite does not contain iron, while pure ferrosillite does not contain magnesium; hypersthene is the name given to the mineral when a significant amount of both elements is present. Particularly developed crystals are rare, the mineral being generally found in the form of foliated masses embedded in the igneous rocks norite and hypersthene-andesite, of which it forms an essential constituent. Coarse-grained labradorite-hypersthene-rock (norite) from Paul Island off the Labrador coast provided the most typical material; for this reason, the mineral has been known as Labrador hornblende or paulite. The color is often gray, brown or green, and the luster is usually glassy to pearly. Pleochroism is strong, the hardness is 5–6, and the specific gravity is 3.4–3.9. On some surfaces, it exhibits a shiny copper-red metallic sheen, or schiller, which has the same origin as the bronzed sheen of bronzite, but is even more pronounced. Like bronzite, it is sometimes cut and polished like a gemstone. The name "hypersthenes" comes from the Greek and means "excessive force", and is an allusion to the fact that it is harder than the mineral hornblende amphibole (a mineral with which it is often confused).