User:Cowdisley/Kiboko Gold Tourmaline

Kiboko Gold Tourmaline
Kiboko Gold Cut Gem
General
CategoryCyclosilicate
Formula
(repeating unit)
NaMg3Al6(BO3)3Si6O18(OH)4
Crystal systemTrigonal
Identification
Formula mass958.75 gm
ColorOrange, yellow.
Crystal habitColumnar - Forms columns; Divergent - Crystals radiate from a center without producing stellar forms;Massive - Uniformly indistinguishable crystals forming large masses.
CleavageIndistinct
FractureUneven, small conchoidal, brittle
Mohs scale hardness7–7.5
LusterVitreous, sometimes resinous
Specific gravity3.06 (+.20 -.06)
Density2.82–3.32
Optical propertiesDouble refractive, uniaxial (-), e=1.612-1.63, w=1.631-1.655, bire=0.0190-0.0250negative
Refractive indexnω=1.635–1.675, nε=1.610–1.650

Kiboko Gold Tourmaline An extremely rare Gold colored Tourmaline that takes its name from the mine near Kiboko[1], a township in Southern Kenya. Kiboko is also the name of a cult derived from ancient Egypt that worshiped the hippopotamus. The township of Kiboko was named after the cult due to the once flourishing supply of Hippopotamus thereabouts. Now days it is primarily known as a rest and recreation center for weary travelers between Narobi and Mombassa [2]. Kiboko was a province of the Sultinate of Hamoud[3], famous for early slave trading. Kiboko Gold Tourmaline can be discerned by the high level of Magnesium. Kiboko Gold Tourmaline is the Dravite variety of the gemstone mineral tourmaline. The name dravite [4]was used for the first time by Gustav Tschermak (1836–1927), Professor of Mineralogy and Petrography, for magnesium-rich (and sodium-rich) tourmaline from the village Unterdrauburg, Drava river area, Carinthia, Austro-Hungarian Empire. This previously unknown Kiboko deposit is marked for the unusual coloration of the dravite with an intense rust orange not seen elsewhere.

The color approximates the yellow-orange of the best fanta-mandarin spessatite[5] garnet. It has the added attraction of an almost Paraiba[6] neon glow and a marked dichroism (yellow to orange depending on the angle of viewing as the gem rotates on its axis).

Rough Kiboko Tourmaline crystal

References

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  1. ^ Derivation of the word in Swahili [1]
  2. ^ Location of village [2]
  3. ^ Sultan Hamoud of Zanzibah [3]
  4. ^ Dravite explained[4]
  5. ^ Reference[5]
  6. ^ Paraiba defined[6]
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