labradorite


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labradorite

(lăb`rədôrīt', lăbrədôr`īt), a variety of plagioclase feldsparfeldspar
or felspar
, an abundant group of rock-forming minerals which constitute 60% of the earth's crust. Chemically the feldspars are silicates of aluminum, containing sodium, potassium, iron, calcium, or barium or combinations of these elements.
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Labradorite

 

(named for a deposit on Labrador), a mineral of the soda-lime feldspars—the plagioclases. It is an isomorphic mixture of soda feldspar (albite) with lime feldspar (anorthite). The mineral contains 50–70 percent anorthite. It crystallizes in the triclinic system; it is colorless, white, or gray and forms complex twins, often with an attractive blue-green and golden iridescence. Its hardness is 6 on the Mohs’ scale and its density is 2,680–2,720 kg/m3. Labradorite enters into the composition of many basic magmatic rocks, including gabbros, basalts, and diabases. Rocks consisting almost entirely of labradorite are called labradoritites.

labradorite

[′lab·rə‚dȯ‚rīt]
(mineralogy)
A gray, blue, green, or brown plagioclase feldspar with composition ranging from Ab50 An50 to Ab30 An70, where Ab = NaAlSi3O8 and An = CaAl2Si2O8; in the course of formation when the natural material cools, the feldspar sometimes exhibits a variously colored luster. Also known as Labrador spar.
References in periodicals archive ?
Muscovite, albite, labradorite and some calcite (calcium carbonate) were also identified in the X-ray diffraction patterns, Figure 1.
The crystals show the schiller effect, like labradorite.
Its range includes: Cappuccino Mocha, Magma Gold, Blue Pearl, Eucalyptus, Alpine Green, Crema San Marco, Verde Fantastic, Juprana Exotica, Indian Green Labradorite and Golden Teak Quartzite.
Her current collection features an endless variety of semi-precious stones such as Labradorite, Russian Amazonite, Moonstone, and Tiger's Eye, and varies from delicate to chunky pieces to reflect her clientele's taste, personality and characteristics.
42) In line with architect Shchusev's plans, the entrance to the mausoleum was flanked in black and grey labradorite, (43) with red granite and raspberry-colored quartzite (44) symbolising the red of the Revolution, and black gabbro (45) symbolising mourning.
There, the gabbros, mostly norite, occasionally troctolite are generally coarse-grained, equigranular to gently pegmatitic, show a texture from cumulate to holocrystalline and are composed by labradorite, augite and subordinate bronzite, with minor amounts of magnetite, ilmenite, and alteration products.
Bainbridge identifies a number of pieces as being his work, including a grey chalcedony donkey in the Royal Collection and a labradorite owl given by Queen Alexandra to her friend Lady De Grey, the Marchioness of Ripon.
In the groundmass, there also occur very small plates of plagioclases: labradorite ([An.
The core composition for all three types of crystals, as determined mainly by extinction angle methods, is bytownite for units A, C, E and G; labradorite for unit B and oligoclase for unit D.
Rubies, emeralds, sapphires, topaz, fire opal, garnet, tourmaline, labradorite, moonstone, and black star obsidian, are just a few of the stones available, all set in silver.
Maderne 'Signature' Fine Jewelry presenting show-stopping one-of-a-kind diamond slices and organic gemstones spanning Aquamarine, Black Onyx, Chalcedony, Green Onyx, Labradorite, Lapis Lazuli, and Rainbow Moonstone surrounded by the most exquisite micro-pave diamond detail and set in 14k white, yellow or rose gold.