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tourmaline
tourmaline
tourmaline A member of the
cyclosilicates and a borosilicate Na(Mg,Fe
2+,Mn,Li, Al)
3Al
6(BO
3)
3[Si
6O
18](OH,F)
4. There are three important members of this family of
minerals: dravite (NaMg
3Al
6(BO
3)
3[Si
6O
18](OH,F)
4);
schorl (Na(Fe
2+,Mn)
3Al
6(BO
3)
3 [Si
6O
18](OH,F)
4); and elbaite (Na(LiAl)
3Al
6 (BO
3)
3[Si
6O
18] (OH,F)
4); sp. gr. 2.9–3.2;
hardness 7.0–7.5;
trigonal; black, bluish, pink, or green, never colourless; elongate
crystals common, also
acicular needles and massive or radiating aggregates;
cleavage good {1120} prismatic; occurs in granite
pegmatites, pneumatolytic (see
PNEUMATOLYSIS) veins, and
granites as elbaite and schorl varieties; it may occur in the rock luxullianite formed by pneumatolytic action after boron has been introduced, where it will occur with
topaz,
spodumene,
cassiterite,
fluorite, and
apatite. Dravite variety occurs in metamorphosed impure
limestones and rarely in some
basic igneous rocks; tourmaline is a common detrital ‘heavy’ mineral in sedimentary rocks. Good multicoloured crystals can be used as gemstones.
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Tourmaline from Malkhanskiy pegmatite district
Magazine article from: Mineralogical Record; 1/1/2001; ; 700+ words
; ...highest in pink tourmaline, ranging up to...content in all tourmalines. Although there...and Ti in pink tourmalines and high Mn and Ti in most yellow tourmalines. This suggests...rich, Fe-poor tourmaline may be the result...
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MOZAMBIQUE TOURMALINE: Fighting the Blue Meanies.(Gem Profile)
Magazine article from: Modern Jeweler; 1/1/2008; 700+ words
; ...that hot new tourmaline producer on Africa...recently discovered tourmalines to unregistered...remarks, "Calling tourmaline from Mozambique...Christie's to call tourmalines from Africa by...lavender and rubellite tourmalines from Madagascar...marvelous purple tourmaline, "the ...
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Paraiba tourmaline. (Jewel of the Month).(Brief Article)
Magazine article from: Jewelers Circular Keystone; 4/1/2002; 700+ words
; ...commercial-quality tourmalines can show surface...When examining any tourmaline, look for enhancement...mislabeled as Paraiba tourmaline or correctly labeled...Paraibas are still tourmalines. You and your...always wise to wash tourmalines with soapy water...Wiping a dry, dusty ...
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Green Tourmalines Resemble Colour of Fine Emeralds.
News Wire article from: PTI - The Press Trust of India Ltd.; 8/27/2008; 700+ words
; Green Tourmalines Resemble Colour...Features) -- Tourmaline continues...occur, iron tourmaline, black schorl...or alkali tourmalines, or elbaites...Fine gem tourmaline comes from...price among tourmalines, the most...
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BROWN TOURMALINE: Earth Tone Poems.(Gem Profile)
Magazine article from: Modern Jeweler; 5/1/2007; 700+ words
; BROWN TOURMALINE: Earth Tone Poems BY DAVID...the many branches of the tourmaline family the bronze, butterscotch, and cinnamon tourmalines we've been seeing in heaping...R.V. Dietrich's The Tourmaline Group, published by Van...
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New tourmaline production from Mount Mica, Maine: America's first gem pegmatite.
Magazine article from: Rocks & Minerals; 11/1/2005; ; 700+ words
; ...Gem-quality elbaite tourmaline was discovered there in 1820...ever since. A new era of tourmaline mining began when Coromoto...pocket with exceptional blue tourmalines (Hamlin 1895). According...carat, flawless blue-green tourmaline nodule that was part of a...
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Tourmaline
Magazine article from: Mineralogical Record; 3/1/2003; ; 700+ words
; ...the chemistry of the tourmaline group; the tourmaline crystal structure...Russian work on Ceylonese tourmalines); the causes of color in tourmalines, leading to two short...history of Burmese tourmaline; "the Kremlin's...
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 "Portland Press Herald (Maine)")
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PRECIOUS COMMODITY [Corrected 05/23/06] ; Tourmaline puts Maine on the map for gem lovers - and Mainers can hunt for it for free.
Newspaper article from: Portland Press Herald (Maine); 5/14/2006; ; 700+ words
; ...COMMODITY [Corrected 05/23/06] ; Tourmaline puts Maine on the map for gem lovers...MINING IN MAINE TO LEARN ABOUT mining for tourmaline in Maine, go to: http://www...Afghanistan, Russia and Africa. Tourmaline ranks the state among these exotic locations...
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History of the Tourmaline Queen mine, San Diego County, California
Magazine article from: Mineralogical Record; 9/1/2002; ; 700+ words
; For over a century the Tourmaline Queen mine near Pala, California...and beautiful crystals of tourmaline and morganite beryl. The...and are surely the finest tourmalines ever recovered in North America...the property known as the Tourmaline Queen Mine. In the immediate...
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History of the Tourmaline Queen mine San Diego County, California.
Magazine article from: The Mineralogical Record; 9/1/2002; ; 700+ words
; For over a century the Tourmaline Queen mine near Pa/a...and beautiful crystals of tourmaline and morganite beryl. The...and are surely the finest tourmalines ever recovered in North America...the property known as the Tourmaline Queen Mine. In the immediate...
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tourmaline
Book article from: A Dictionary of Earth Sciences
tourmaline A member of the cyclosilicates and a borosilicate Na(Mg,Fe 2+ ,Mn...metamorphosed impure limestones and rarely in some basic igneous rocks; tourmaline is a common detrital ‘heavy’ mineral in sedimentary...
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Cyclosilicates
Book article from: World of Earth Science
...varieties emerald and aquamarine, and tourmaline. Beryl, found in granite , pegmatites...the metal beryllium. Minerals in the tourmaline group, found in granite pegmatites...and sedimentary rock . Varieties of tourmaline include schorlite, also called black...
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Aepinus, Franz Ulrich Theodosicus
Dictionary entry from: Complete Dictionary of Scientific Biography
...preoccupation at the time was the study of the tourmaline, to which he was introduced by Wilcke...of the attractive power of a warmed tourmaline and attempted not altogether successfully...by the formal similarity between the tourmaline and the magnet in regard to polarity...
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polarization of light
Book article from: The Columbia Encyclopedia, Sixth Edition
...Polarized light can also be produced by using a tourmaline crystal. Tourmaline (a double-refracting substance) removes one...crystals of some polarizing substance such as tourmaline. The solution to be tested is placed between...
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Herapath, William Bird
Dictionary entry from: Complete Dictionary of Scientific Biography
...referred to this compound as artificial tourmaline and discussed its advantage in optics...of Polarizing a Ray of Light, Like Tourmaline, and at Certain Angles of Rotation...for Optical Purposes as Artificial Tourmalines, ” ibid ., pp. 346...
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