Gypsum is a soft sulfate mineral, calcium sulfate dihydrate with the formula CaSO4·2H2O, and the Mohs scale defines it as hardness 2. It forms as an evaporite mineral in lake and sea water and as a hydration product of anhydrite, and it is the most common sulfate mineral. It occurs as flattened, often twinned crystals, as transparent cleavable selenite, as silky fibrous satin spar and as fine-grained white alabaster, and in arid areas as the flower-like desert rose. Selenite forms some of the largest crystals found in nature, up to 12 metres long. Gypsum is widely mined for plaster, drywall, blackboard chalk and fertilizer, and heating it in air drives off water to give plaster. The White Sands dunes of New Mexico are a rare expanse of gypsum sand.
Facts
Formation ClassEvaporite (forms as an evaporite mineral and as a hydration product of anhydrite) 1 Chemical FormulaCaSO4 2H2O (calcium sulfate dihydrate) 1 Hardness (Mohs) Classification
Strunz Class Crystal System UseBuilding and Construction 1 UseSoil Amendment or Fertilizer 1 Connections
Associated With
Source Cave of the Crystals (Wikipedia)
Source Wikipedia: Devils Tower - Wikipedia
Gypsum named as one of the most common marine evaporite minerals.
Source Evaporite (Wikipedia)
Source Magdalen Islands (Wikipedia)
The Mohs scale defines gypsum as hardness value 2.
Source Gypsum (Wikipedia)
Source Tagus Basin (Wikipedia)
Source Zagros Mountains (Wikipedia)
Caused By
Source Gypsum (Wikipedia)
Source EBSCO Research Starters: Sedimentary rock classification
Additional Source Gypsum (Wikipedia)Article text
Source Gypsum (Wikipedia)
Classified As
Crystallizes In System
In Discipline
Source Gypsum (Wikipedia)
In the Other Atlases
Mineral Species Of
Also in Divinity Atlas: of this mineral species.
Sources
1. Gypsum (Wikipedia)
Wikimedia FoundationLead section
The Mohs scale of mineral hardness defines gypsum as hardness value 2 based on scratch hardness comparison.
Lead section
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O.
Infobox: system
Monoclinic
Article text
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.
Caused By: Hydrothermal Circulation, Occurrence
Gypsum is deposited from lake and sea water, as well as in hot springs, from volcanic vapors, and sulfate solutions in veins.
Caused By: Supergene Processes, Occurrence
Gypsum is also formed as a by-product of sulfide oxidation, amongst others by pyrite oxidation, when the sulfuric acid generated reacts with calcium carbonate.
View the Source 2. minerals.net: Gypsum
minerals.netColor field
Colorless, white, gray, brown, beige, orange, pink, yellow, light red, green
Luster field
Vitreous to pearly
Description
Gypsum is a very common mineral
View the Source Wikidata: Gypsum
Wikidata Q82658
Evaporite (Wikipedia)
Wikimedia FoundationAssociated With: Evaporite, Marine evaporite minerals sectionQuote, Associated With: Evaporite, Marine evaporite minerals section
The most common marine evaporites are calcite, gypsum and anhydrite, halite, sylvite, carnallite, langbeinite, polyhalite, and kainite.
Cave of the Crystals (Wikipedia)
Associated With: Cave of Crystals, Article text, rock GypsumQuote, Associated With: Cave of Crystals, Article text, rock Gypsum
When the overall temperature of the cave started to drop below 56 °C (133 °F), the hydrothermal and sedimentary anhydrite crystals dissolved, and gypsum (CaSO4·2H2O) crystals formed.
Wikipedia: Devils Tower - Wikipedia
Associated With: Devils Tower, Article text, rock GypsumQuote, Associated With: Devils Tower, Article text, rock Gypsum
Above the Spearfish Formation is a thin band of white gypsum, called the Gypsum Springs Formation, Jurassic in age.
Magdalen Islands (Wikipedia)
Associated With: Magdalen Islands, Article text, rock GypsumQuote, Associated With: Magdalen Islands, Article text, rock Gypsum
Where volcanic effusions have come into contact with sandstones, large masses of gypsum are found.
Tagus Basin (Wikipedia)
Associated With: Tagus Basin, Article text, rock GypsumQuote, Associated With: Tagus Basin, Article text, rock Gypsum
In the interior of the area defined by these mountains and by the minor reliefs of the Hercynian massif, which completes the closure to the west, it is structured in a graben filled by Cenozoic materials, sands, clays, marls, gypsum and some limestone in the upper levels, which constitute horizons of silting up of the ancient lake that occupied the original depression.
Zagros Mountains (Wikipedia)
Associated With: Zagros Mountains, Article text, rock GypsumQuote, Associated With: Zagros Mountains, Article text, rock Gypsum
There is also much water-soluble gypsum in the region.
EBSCO Research Starters: Sedimentary rock classification
EBSCO Research StartersCaused By: Sedimentation, EvaporitesQuote, Caused By: Sedimentation, Evaporites
The main groups of sedimentary rocks include evaporites, which form from the evaporation of seawater or freshwater, resulting in minerals like gypsum and halite.
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