Gypsum
The chemical formula for gypsum is CaSO 4.2H 2 O (calcium sulfate dihydrate). Gypsum forms typical monoclinic crystals. Most often, it forms in perfect tabular crystals, but it can also appear as acicular (long and thin) crystals in large bundles, rosettes, grainy or scaly crystals, fibrous veins, and lenticular crystals.
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Gypsum | Common Minerals
Gypsum also occurs in crystal form, with the two most common varieties being large clear crystals that are often termed selenite, and fibrous crystals, known as satin spar. 'Selenite' is the Greek word for moon, and refers to the crystals well-developed pearl-like luster that can reflect a … See more
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satin spar vs. selenite: are they the same?
Varieties of gypsum. Selenite: This is what most people consider to be real, natural selenite. It forms in large, transparent slabs that flake easily; Golden healer selenite: Normal selenite with iron inclusions …
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Minerals | SpringerLink
Prismatic, columnar, bladed, acicular/needle-like, or fibrous—rod-shaped crystals, including, tourmaline (acicular prisms), gypsum and calcite (columnar), topaz, rutile and amphibole ... Cleavage can be perfect (mica—in 1 direction, calcite—in 3 directions), good (gypsum), indistinct/poor (apatite, chalcopyrite), or a mineral may have …
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Gypsum: Meaning, Properties, and Benefits You Should Know
Fibrous Gypsum: It has thin white threads that look like snow and make your room feel safe. Gypsum with Pharmacolite: This crystal pair of pure white Gypsum and delicate …
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Petrography and isotopic geochemistry of bedding-parallel fibrous …
The fibrous gypsum crystals in our samples show optical continuity and constant width in growth direction, suggesting that growth of fibrous gypsum crystals is more likely to be a continuous process. In crack-seal theory by Ramsay (1980), antitaxial fibrous vein growth occurs in vein-wall interface due to low cohesion, and is driven by …
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14.9: Sulfate Minerals
Acicular, fibrous, reniform, or granular crystals are also common. Structure and Composition Although in principal a complete solid solution exists between celestite (SrSO 4) ... Typical gypsum crystals are tabular (like the ones seen in Figure 14.414, above), thick to thin, often forming as elongated sheaves or masses.
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Crystal Habits and Forms of Minerals and Gems
These enormous crystals of selenite gypsum have a columnar habit. They are in the "Cave of the Crystals" cavern, Chihuahua, Mexico (a person in the lower-right quadrant of the photo serves as scale). ... The actinolite crystals on this rock have a fibrous habit. Because of their fibrous shape (a roughly 1:20 aspect ratio) and properties ...
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Definition of fibrous structure
Definition of fibrous structure. i. If the crystals in a mineral aggregate are greatly elongated and have a relatively small cross section, the structure or texture is fibrous. The fibers may be parallel, as in crocidolite and sometimes in gypsum and cerussite. When the fibers are very fine, they may impart a silky luster to the aggregate, as ...
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Petrography and isotopic geochemistry of bedding-parallel fibrous
The gypsum crystals making up the vein fill grew perpendicular to the fracture walls, suggesting that opening and filling of the fractures was contemporaneous and that the fractures are ...
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Gypsum crystals in soils | Request PDF
In sediments of the Kamchatka hot springs, we observed prismatic, prismatic pseudo-hexagonal, fibrous, tubular, lenticular and twinned gypsum crystals, with crystal sizes ranging from <200 nm to ...
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All About Gypsum – Uses, Properties, Color, and Worth
Additionally selenite, the most popular form of gypsum, can form as fibrous silky crystals called "satin spar". Gypsum can even form as fine grained crystals called alabaster which is commonly used in ornamental applications, or carvings, due to its soft and translucent nature.
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Selenite: Align and Flow with Light | Enter The Earth
Selenite is a common name for the mineral gypsum. Historically it was only used for transparent crystals and the white fibrous variety was called satin spar instead. (Since the latter was also used for fibrous calcite and aragonite, scientific sources use the name as a prefix instead. This material is labeled satin spar gypsum.)
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Gypsum Value, Price, and Jewelry Information
Gypsum crystals may form in curved shapes that resemble the horns of a ram. "Ram's horn" selenite crystal, 9.7 x 8.2 x 4.6 cm, Guangdong Province, ... Lapidaries could cut cabochons and carvings of almost size desired from massive gypsum. Fibrous material could yield large carvings up to several pounds. Faceted selenites could reach hundreds …
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Gypsum Flowers
Gypsum Flowers. Flowers are speleothems with crystal petals radiating from a central point. The petals are fibrous or prismatic crystals growing in a parallel orientation. They are usually made of sulfate minerals such as gypsum or epsomite, but can form from halite, or rarer (for caves) minerals, and even ice.
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Gypsum flowers and related speleothems
Gypsum and the related sulfate minerals mirabilite and epomite crystallize in dry caves in a variety of speleothems. Among these are crusts, stalactites, gypsum flowers, and some very thin fibrous forms known as cave cotton and angel hair. Gypsum flowers are formed of curving, fibrous crystals that radiate outward from a growth center ...
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Gypsum: Mineral information, data and localities.
Satin Spar Gypsum: A fibrous variety of Gypsum. See also the main page on Satin Spar. Selenite: The name 'selenite' is mostly synonymous with gypsum but has been used historically to describe the transparent variety, as opposed to satin spar gypsum for the fibrous variety and alabaster for the fine-grained massive form. The original name was ...
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Mini Me Geology BlogRocks and Minerals We Love: GYPSUM MINERALS …
The name Gypsum comes from the Greek word gypsos, which means plaster and mentions of the minerals are known beginning approximately 300 BC. Around the globe, gypsum forms in massive chunks, clear crystals, and as fibrous bundles. Gypsum is a soft mineral and was chosen as an example mineral by Friedrich Mohs for …
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Selenite | Properties, Formation, Occurrence» Geology Science
Modified date: 06/03/2024. Selenite is a beautiful and versatile mineral that belongs to the gypsum mineral family. It is composed of hydrous calcium sulfate and is known for its transparent to translucent appearance. Selenite crystals often exhibit a pearly or glass-like luster and have a unique fibrous or columnar structure.
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The geochemical riddle of "low-salinity gypsum" deposits
1. Introduction. Gypsum (CaSO 4 ·2H 2 O) accounts for approximately 20% of the minerals in giant salt deposits formed via the evaporation of seawater throughout Earth's history (Zharkov, 1981, Warren, 2006).Its ionic components SO 4 2− and Ca 2+ are the fourth and fifth most abundant dissolved ions of seawater (Stumm and Morgan, …
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Gypsum flower | geology | Britannica
Other articles where gypsum flower is discussed: cave: Depositional materials and features: …of fibrous crystals known as gypsum flowers. Because of their higher solubility, sulfate minerals either do not occur or are destroyed in damp or wet caves.
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Gypsum | Definition, Uses, & Facts | Britannica
gypsum, common sulfate mineral of great commercial importance, composed of hydrated calcium sulfate (CaSO 4 ·2H 2 O). In well-developed crystals the mineral commonly has been called selenite. …
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(PDF) Syn- and Post-tectonic gypsum cements in fractured gypsum …
Fibrous gypsum cement formed by fibres up to 3 cm length.2. Millimetrical gypsum crystals in contact with host-gypsum rock. 3. Photomicrograph of aligned gypsum cement. 4. Outcrop image of microcrystalline cement GEOFLUIDS VII - Guidelines for Paper Preparation 2 • Macrocrystalline cement Euhedral to sub-euhedral gypsum crystals, up …
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The 7 Different Types Of Gypsum (With Photos)
Gypsum is a mineral so versatile that it can look like glass, feel like silk, or even blossom in the desert like a flower. ... Because of its fibrous nature, it can also be carved into beautiful shapes and objects, making it a popular choice for artisan crafts and decorative items. ... This happens because the gypsum crystals grow in a way that ...
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Gypsum | GeoKansas
Gypsum outcrop in Clark County. Gypsum is an evaporite because it precipitates (settles) out of water as the water evaporates. the three varieties of gypsum are selenite, satin spar, and rock gypsum. Selenite, found throughout the Red Hills, has flat, diamond-shaped crystals that can be split into thin sheets.Satin spar is white or pink and fibrous with a …
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Petrography and isotopic geochemistry of bedding-parallel fibrous …
The median zone is characterized by blocky gypsum crystals and multiple host rock fragments formed by crack-seal events. The fibrous zone is composed of parallel gypsum fibres a high angle to the vein walls, indicating shear component. Vein opening is considered to be the result of fluid overpressure caused by horizontal compression in low ...
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The 7 Different Types Of Gypsum (With Photos)
This special shine comes from its fibrous crystal structure, which scatters light in a way that makes it look almost like it's glowing from within. As a type of gypsum, …
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Sedimentological implications of microbial mats, gypsum, …
The micritized, microbial laminae may also form a lateral, straight-sided, bridge connecting the crests of adjacent swallowtail crystals. Such bridges overlie a primary, intercrystalline cavity enclosed between adjacent gypsum crystals, and overlain with clastic gypsum and radial growth of fine, fibrous and swallowtail gypsum crystals …
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Satin Spar vs Selenite: Comparing Properties, Benefits, and …
Satin Spar is commonly referred to as "fibrous gypsum" because of its long and thin fibrous crystal formation. This gives it a silky, satin-like luster, from where it gets its name. Selenite typically forms in large, transparent, tabular crystals with …
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Gypsum Mineral Data
Scale: Specimen size 5 cm. © Dave Barthelmy. Gypsum Crystallography. Axial Ratios: a:b:c =0.3741:1:0.4143. Cell Dimensions: a = 5.68, b = 15.18, c = 6.29, Z = 4; beta = …
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