Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywall. Alabaster, a fine-grained white or lightly tinted variety of gypsum, … See more The word gypsum is derived from the Greek word γύψος (gypsos), "plaster". Because the quarries of the Montmartre district of Paris have long furnished burnt gypsum (calcined gypsum) used for various purposes, this … See more Gypsum occurs in nature as flattened and often twinned crystals, and transparent, cleavable masses called selenite. Selenite contains no significant See more Commercial quantities of gypsum are found in the cities of Araripina and Grajaú in Brazil; in Pakistan, Jamaica, Iran (world's second largest … See more Synthetic gypsum is produced as a waste product or by-product in a range of industrial processes. Desulfurization Flue gas desulfurization gypsum (FGDG) is recovered at some coal-fired power plants. The main … See more Gypsum is moderately water-soluble (~2.0–2.5 g/L at 25 °C) and, in contrast to most other salts, it exhibits retrograde solubility, becoming less soluble at higher temperatures. When gypsum is heated in air it loses water and converts first to calcium sulfate hemihydrate See more Gypsum is a common mineral, with thick and extensive evaporite beds in association with sedimentary rocks. Deposits are known to occur in strata from as far back as the Archaean eon. Gypsum is deposited from lake and sea water, as well as in hot springs, … See more People can be exposed to gypsum in the workplace by breathing it in, skin contact, and eye contact. Calcium sulfate per se is nontoxic and is even approved as a food additive, but as … See more
Gypsum Mineral Data - Mindat.org
WebWe explored spectral diversity in infrared (IR, 4–25 μm) imaginary (k) and real (n) indices of refraction (optical constants) for 26 surface soils that originated from global dust entrainment regions. The k spectra were derived from optical transmission spectra of KBr pellets containing dispersed dust and the n spectra were estimated with the subtractive … WebOct 12, 2007 · [1] Diffuse reflectance spectra of multiple grain size fractions are used to estimate the optical constants of gypsum over the 0.4–15 μ m wavelength region. Two … british colonialism in egypt
Daily Gypsum Drop-Rates: Which Ones Are Easiest to Obtain and …
WebApr 19, 2010 · II . Plagioclase feldspar (isomorphous) Oligoclase feldspar from Tanzania. Feldspar is a group of minerals that are very important in rock formation, accounting for over half of Earth's crust! There are a … WebApr 1, 1993 · The complex indices of refraction for crystalline gypsum and calcite were determined from reflectance measurements for both single crystals and pressed powder … WebApr 10, 2024 · In this paper, individual particle analysis by automated scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX) was used to assess the size-resolved information of composition, size distribution, complex refractive index, and mixing state of mineral dust aerosol particles collected using different passive and active … british colonial pith helmets