anhydrite : List Of Minerals : The Stone Network
The Business To Business Portal For The Natural Stone Trade

Premium Black Galaxy Granite Slabs
Direct From The Factory
Ex-India

Mobile

Directory

Stone Fairs

Exhibitions 2017 Country
Exhibitions 2017 By Date

Stone Images

Granite
Limestone
Marble
Onyx
Quartzite
Sandstone
Slate
Travertine

Stone Machines

New Stone Machines
Used Stone Machines

Stone Sites

Stone Forums
Stone Magazines
Stone Portals

Stone Standards

CE Marking

Stone Supplies & Fabricators

Australia
Canada
United Kingdom
U.S.A.

Stone Testing

ASTM
BRE
Sandberg
Stats
Stone Initiatives
UKAS

Petrology

Granite
Limestone
Marble
Quartzite
Sandstone
Slate
Travertine

Rocks

Igneous
List of Minerals
List of Rocks
Metamorphic
Minerals
Sedimentary

Various Resources

A To Z Stone Names
Anti Slip
BIDA
Building Conservation
Building Design
English Heritage
Maintenance Products
Natural Stone Database
RIBA
RICS
Salvo
SPAB
Stone Federation GB
Trade Terminology

Anhydrite is a mineral - anhydrous calcium sulfate, CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the orthorhombic barium (barite) and strontium (celestine) sulfates, as might be expected from the chemical formulas. Distinctly developed crystals are somewhat rare, the mineral usually presenting the form of cleavage masses. The hardness is 3.5 and the specific gravity 2.9. The colour is white, sometimes greyish, bluish or purple. On the best developed of the three cleavages the lustre is pearly, on other surfaces it is vitreous. When exposed to water, anhydrite readily transforms to the more commonly occurring gypsum, (CaSO42H2O) by the absorption of water. Anhydrite is commonly associated with calcite, halite, and sulfides such as galena, chalcopyrite, molybdenite, and pyrite in vein deposits.

Anhydrite is most frequently found in salt deposits with gypsum; it was, for instance, first discovered, in 1794, in a salt mine near Hall in Tirol. In this occurrence depth is critical since nearer the surface anhydrite has been altered to gypsum by absorption of circulating ground water.

From an aqueous solution calcium sulfate is deposited as crystals of gypsum, but when the solution contains an excess of sodium or potassium chloride anhydrite is deposited if temperature is above 40C. This is one of the several methods by which the mineral has been prepared artificially, and is identical with its mode of origin in nature, the mineral is common in salt basins.

The name anhydrite was given by A. G. Werner in 1804, because of the absence of water of crystallization, as contrasted with the presence of water in gypsum. Some obsolete names for the species are muriacite and karstenite; the former, an earlier name, being given under the impression that the substance was a chloride (muriate). A peculiar variety occurring as contorted concretionary masses is known as tripe-stone, and a scaly granular variety, from Vulpino, near Bergamo, in Lombardy, as vulpinite; the latter is cut and polished for ornamental purposes.

  • Chicken-wire anhydrite
  • Chicken-wire anhydrite is a type of anhydrite deposit where seeping ground water gradually deposited large amounts of anhydrite in the sediment, replacing most of it, so that a cross-section of it looks somewhat like the coarse wire netting often used to confine poultry.

    Trade Supplies
    Information
    Information
  • Absolute Black Granite : Black Galaxy, Star Galaxy, Nero Impala etc. Black is popular, black looks great, black is more expensive >>>
  • Black Galaxy Granite : Quarrying & Quality Information >>>
  • M.I.A. Information
    Copyright :
    Legal Information
    This web site is protected under International Law by the
    Digital Millennium Copyright Act 1998.

    If you wish to link to this site please feel free to do so HOWEVER blatant design copying, code copying and theft of bandwidth will result in legal action!

    Digg Logo ImageDigg Facebook Logo ImageFacebook Reddit Logo ImageReddit StumbleUpon Logo ImageStumbleUpon Twitter Logo ImageTwitter

    Home : Contact : About : Legal : Privacy : Cookies : Copyright 1998-2017 : The Stone Network