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Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO 4 ·2H 2 O. [4] It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, drywall and blackboard or sidewalk chalk.
Black alabaster is a rare anhydrite form of the gypsum-based mineral. The black form is found in only three veins in the world, one each in United States, Italy, and China. Alabaster Caverns State Park, near Freedom, Oklahoma, is home to a natural gypsum cave in which much of the gypsum is in the form of alabaster. There are several types of ...
An ancient Roman grave filled with white gypsum was found in England, officials announced last week. The material was reportedly used to make plaster.
Selenite, satin spar, desert rose, and gypsum flower are crystal habit varieties of the mineral gypsum.. All varieties of gypsum, including selenite and alabaster, are composed of calcium sulfate dihydrate (meaning that it has two molecules of water), with the chemical formula CaSO 4 ·2H 2 O. Selenite contains no selenium, the similar names both derive from Greek selḗnē (σελήνη 'Moon').
The gypsum is mostly in the form of alabaster. There are several types of alabaster found at the site, including pink, white, and the rare black alabaster. This black alabaster can be found in only three veins in the world, one each in Oklahoma, Italy and China. Another form of gypsum can be found in the many selenite crystal formations. [4]
It is mainly composed of gypsum (CaSO 4 ·2H 2 O). Although gypsum is a widely used material in the construction industry , phosphogypsum is usually not used, but is stored indefinitely because of its weak radioactivity caused by the presence of naturally occurring uranium (U) and thorium (Th), and their daughter isotopes radium (Ra), radon (Rn ...
Iron ore (banded iron formation) Manganese ore – psilomelane (size: 6.7 × 5.8 × 5.1 cm) Lead ore – galena and anglesite (size: 4.8 × 4.0 × 3.0 cm). Ore is natural rock or sediment that contains one or more valuable minerals, typically including metals, concentrated above background levels, and that is economically viable to mine and process.
The typical cap rock is a salt, topped by a layer of anhydrite, topped by patches of gypsum, topped by a layer of calcite. [8] Interaction of anhydrite with hydrocarbons at high temperature in oil fields can reduce sulfate (SO 2– 4) into hydrogen sulfide (H 2 S) with a concomitant precipitation of calcite. [9]