Gypsum is a very soft mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4Â-2H2O.
Contents
1 Crystal varieties
2 Occurrence
3 Uses of Gypsum
4 References ...
Gypsum
Gypsum is a white mineral which is usually used to make Plaster of Paris.
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Gypsum
A white mineral usually used to make Plaster of Paris.
Halogen ...
Gypsum: A soft, white mineral composed of hydrous sulfate of lime. It is used as plaster of Paris.
Gypsy setting: A setting in which the surface of the mount is virtually flush with the top of the gemstone.
Gypsum is a soft mineral composed of calcium sulfate dihydrate. Gypsum occurs in nature as flattened or twinned crystals and transparent cleavable masses called selenite. When Gypsum has a silky and fibrous texture it is called Satin Spar.
Gypsum
Ellis Co.
Gypsum - Former collection of Joe McIntosh, 9.0cm x 3.2cm ...
Gypsum, var. Selenite is common at Philips Mine as micro crystal coatings in cavities and on other minerals. It is likely that these crystals formed since mining began as it is visible in the tunnels and on heavily decayed minerals on the dump.
gypsum
Gypsum is a sedimentary rock that is formed by the chemical precipitation of calcium, sulfur, and oxygen.
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Rock and Mineral Dictionary ...
Gypsum.- Present in the emerald formation as well-formed, clear, slender crystals. Presumably a weathering mineral, but Lleras Codazzi47 noted inclusions of parisite, and Olden48 mentioned green gypsum as an associate of the emerald.
Gypsum (CaSO4-2H2O) is the most prevalent and important of the hydrous sulfates. It possesses a sheetlike structure which consists of layers of calcium ions and sulfate anions separated by water molecules (H2O).
Other names/forms:
Gypsum
Most distinguishing features:
Identified by hardness and good cleavage.
AngeliteAngelite (CaSO4); it is a pale blue variety of calicium sulfate = anhydrate (it is gypsum that has lost water and crystallized). The stone is quite brittle; crystals are transparent to transluscent. Angelite stone has a hardness of 3 to 3.
Silky - A fibrous sort of luster, often display chatoyancy (Gypsum)
Silicates - Mineral containing silicon and oxygen, along with other elements.
Soft Paste Porcelain - The early European porcelain mixture of ground glass or frit for translucency (frit was a mixture of white sand, gypsum, soda, alum, salt and nitre melted together in a mass, then broken and pulverized), ...
It can be confused with selenite gypsum, but while selenite is very soft and can be scratched with a fingernail, moonstone is relatively hard.
Chrysocolla, Chlorite, Copper, Covellite, Calcite, Cuprite, Caledonite, Cerussite, Cobaltite, Chalcopyrite, Chenite, Chrysocolla, Descloizite, Devilline, Erythrite, Elyite, Fluorapatite, Fluorite, Goethite, Gold, Greenockite, Gypsum, ...
Alabaster: A form of mineral gypsum that can be used for beads.
Alexandrite: A gemstone named after Alexander tsar of Russia.
Fluorite at 4 is not twice as hard as gypsum at 2; nor is the difference between calcite and fluorite similar to the difference between corundum and diamond. An absolute hardness scale looks a little different than the relative scale.
Overview: Selenite is the name given to colorless, transparent Gypsum. Selenite denotes the clear crystal variety that is less common. Selenite is the natural version of fiber optics.
This substance is sulphate of lime or gypsum of a white or delicately tinted colour. It is one of the softest minerals known to nature and is therefore used as an ornamental stone in sculpture, though only for internal work as it weathers easily.
5d is a common form for selenite (gypsum). Many common minerals crystallize in this symmetry class, including azurite, clinopyroxene and clinoamphibole groups, datolite, epidote, gypsum, malachite, orthoclase, realgar, titanite, spodumene, and talc.
Chrysanthemum Rock is is a black and white rock made up of Gypsum clay, Dolomite and Limestone, with internal crystals of Calcite, Feldspar, ...
(d) Monoclinic: In this system all the crystals have three axes of which are not of equal lengths and two of them are not perpendicular to one another, but are both perpendiculars to the third axes. Gypsum is an example of this system.
1. Talc 6. Orthoclase 2. Gypsum 7. Quartz 3. Calcite 8. Topaz 4. Fluorite 9. Corundum 5. Apatite 10 Diamond This scale is approximately linear up to corundum, but diamond is approximately 5 times harder than corundum.
Silky: Some fibrous minerals such as gypsum and malachite have a silky luster.
Pearly: Pearls are composed of layers of nacre from which light is reflected at and near the surface.
Angelite: A pale blue variety of calcium sulfate. (A gypsum that has lost water and crystallized). The stone isbrittle and the crystals are transparent to translucent).
Angelskin Coral: A highly valued pale pink coral.
Alabaster: A form of the mineral gypsum which is usually white or grey in color. It is often used in sculpture, stone paneling, beads, and cabochons.
Alabaster A variety of gypsum (a mineral) which is translucent and milky white, and can be carved into beads or statues.
sedimentary rocks and evaporative rocks. Sometimes metamorphosed from dehydrated gypsum.
Association:
dolomite, gypsum, sylvite, calcite ...
Alabaster: A white, opaque or translucent form of the mineral gypsum which is usually white or grey in color. It is often used in sculpture, stone paneling, beads, and cabochons.
The ten-point scale of mineral hardness, keyed arbitrarily to the minerals talc, gypsum, calcite, fluorite, apatite, orthoclase, quartz, topaz, corundum, and diamond.
Treated Diamond ...
Alabaster
Alabaster is a form of mineral gypsum that can be used for beads.
Selenite is a soft, colorless-to-slightly-colored, transparent mineral. It is a crystalline variety of gypsum. Selenite has a hardness of 1-2 and a specific gravity of 2.3 to 2.4.
SELINI ...
The products of the group other than diamonds comprises of Alumina, aluminum and bauxite, borates, coal, copper, diamonds, gold and silver, gypsum, iron ore, molybdenum, salt, sulphuric acid, talc, titanium dioxide, uranium and other products.
Gypsum
1. Talc (softest)
Because the numbers are based on properties of actual stones, they are not equally distributed. So the difference between 10 (diamond) and 9 (sapphire) is not equal to the difference between any other two numbers.
Alabaster
Translucent and milky white, the mineral Alabaster is a variety of gypsum ...
MOHS SCALE - A loose scale of hardness, used for field collecting, which allows for identification of specimens. The comparative scale of hardness is as follows: 1) talc, 2) gypsum, 3) calcite, 4) fluorite, 5) apatite, 6) orthoclase, 7) quartz, 8) ...
From hardest to softest, his list includes the following: 10 is diamond, 9 is sapphire, 8 is topaz, 7 is quartz, 6 is orthoclase feldspar, 5 is apatite, 4 is fluorspar (fluorite), 3 is calcite, 2 is gypsum, and 1 is talc.
The Mohs Scale is a commonly used scale that compares mineral hardness. For example, diamond (the hardest mineral) is rated at 10 on the Mohs Scale, while gypsum (a very soft mineral) is rated at 2.
[Minerals from briny evaporates: "cranberry halite" from Nevada, green halite from Australia (color is due to pigments from crustaceans and microorganisms that lived in the salty water), gypsum "roses": Images courtesy of Las Vegas Jewelry and ...
SCALE - A loose scale of hardness, used for field collecting, which allows for identification of specimens. Devised by Friedrich Mohs, a German mineralogist, in the 19th century. The comparative scale of hardness is as follows:
1) talc
2) gypsum ...
Aragonite is sometimes deposited from hot springs and can be found occasionally in association with beds of gypsum and some iron oxide deposits
Metaphysical/ Medical Properties: Provides for ease and is useful during periods of stress and anger.
formed originally of sediment, including shale and sandstone, composed of fragments of other rocks deposited after transportation from their sources, and including those formed by precipitation, as gypsum, ...
Mohs' scale: The most commonly used scale of relative hardness of minerals: diamonds, 10; corundum (ruby and sapphire), 9; topaz, 8; quartz, 7; feldspar, 6; apatite, 5; fluorite, 4; calcite, 3; gypsum, 2; talc, 1.
Mohs' Scale A hardness scale invented by Friedrich Mohs which is based on diamond (10), the hardest known substance to man. Corundum 9; topaz 8; quartz 7; feldspar 6; apatite 5; fluorite 4; calcite 3; gypsum 2; talc 1.
the 'Alpine rose' formed by Hematite and the 'Desert rose' formed by a variety of gypsum.
A rose diamond.
An ornament of ivory cut in the form of a rose, first made at Dieppe, France, and later at Erbach, Germany.
assessment of “scratch hardness' by ranking 10 different stones from hardest to softest. His list includes the following:
10. Diamond (Hardest)
9. Sapphire
8. Topaz
7. Quartz
6. Orthoclase Feldspar
5. Apatite
4. Fluorspar
3. Calcite
2. Gypsum
1.
but also from the fact that various directions on a given stone's surface show a considerable variation in resistance to abrasion. The hardest direction in diamond is parallel to the faces of the octahedron.
1.Talc 6. Orthoclase feldspar
2. Gypsum ...
True topaz (precious topaz) he called 8. Quartz (amethyst and quartz "topaz") was given the number 7. Felspar (moonstone) was rated 6, the mineral apatite 5, fluorspar 4, calcite 3, gypsum 2, and talc 1.
For example, in actual hardness, the diamond has been found to be up to 150 times as hard as corundum, the next lower on this scale.According to scale, the hardness in order is:1- Talc 2 - Gypsum 3 - Calcite 4 - Fluorite 5 - Apatite 5.5-6.
Many cameos were forged from other materials as glass ("Tassies"), porcelain and even gypsum. Cameo doublets also were not uncommon. The themes of these cameos were almost always derived from classical mythology and portraits.
 See also: Mineral, Crystal, Stone, Minerals, Color
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