Hypersthene is a common rock-forming inosilicate mineral belonging to the group of orthorhombic pyroxenes . Its chemical formula is (Mg,Fe)SiO 3 . It is found in igneous and some metamorphic rocks as well as in stony and iron meteorites . Many references have formally abandoned this term, preferring to categorise this mineral as enstatite or ferrosilite . It forms a solid solution series with the minerals enstatite and ferrosilite, being a mid-way member between the two. Pure enstatite contains no iron, while pure ferrosilite contains no magnesium; hypersthene is the name given to the mineral when a significant amount of both elements are present. Enstatite is stable at atmospheric pressure, but ferrosilite is stable only at elevated pressure, decomposing into quartz and fayalite at atmospheric pressure unless stabilized by magnesium or other impurities.
5-398: Baltimore Gabbro Complex is a hypersthene gabbro with subordinate amounts of olivine gabbro, norite , anorthositic gabbro, and pyroxenite . Igneous minerals and textures are well preserved in some rocks, and other rocks exhibit varying degrees of alteration and recrystallization with a new metamorphic mineral assemblage. Baltimore Gabbro Complex was an early roadbed material for
10-446: Is often gray, brown, or green, and the luster is usually vitreous to pearly. The pleochroism is strong, the hardness is 5–6, and the specific gravity is 3.4–3.9. On certain surfaces it displays a brilliant copper-red metallic sheen, or schiller, which has the same origin as the bronzy sheen of bronzite , but is even more pronounced. Like bronzite, it is sometimes cut and polished as a gemstone . The name "hypersthene" comes from
15-675: The Central Maryland Region. It was specified as "trap" or " nigger-head ". It was mined in the Stoney Forest area of Harford and Cecil Counties, along the Susquehanna in Baltimore and as far south as Laurel. In 1996, Kingdon Gould III 's Laurel Sand and Gravel company which includes Fairfax Materials, Allegany Aggregates, Laurel Asphalt and S.W. Barrick & Sons purchased the 600 acres chase property north of
20-524: The historic town of Savage, Maryland . The site is home to the Savage Stone quarry, mining Baltimore Gabbro for road bed construction. The material is amble to support 50,000 pounds per square inch for road construction. The facility started operations in 2005 after special zoning approval with a 25-year reserve in materials. Baltimore Gabbro Complex is Paleozoic , post- lower Ordovician . Hypersthene Distinctly developed crystals are rare,
25-399: The mineral being usually found as foliated masses embedded in the igneous rocks norite and hypersthene- andesite , of which it forms an essential constituent. The coarse-grained labradorite -hypersthene-rock (norite) of Paul's Island off the coast of Labrador has furnished the most typical material; for this reason, the mineral has been known as Labrador hornblende or paulite. Color
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