Difference between revisions of "Paraiba"

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{{Paraiba}}
 
{{Paraiba}}
  
[[Image:Paraiba.jpg|left|framed|Brazilian Paraiba tourmaline]]<br clear="left" />
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[[Image:Paraiba1.jpg|left|thumb|250px|Brazilian Paraiba tourmaline <br /> Photo courtesy of Lembeck Gems]]<br clear="all" />
  
[[Image:Mozparaiba.jpg|left|framed|Mozambique "Paraiba" tourmaline <br />Photo courtesy of <br />Precision Gem]]<br clear="left" />
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==Paraiba type==
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{| align="center" {{table}} style="margin:0;"
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|-
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|align="center"|
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[[Image:Mozparaiba.jpg|200px]]
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|align="center"|
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[[Image:6403_d.jpg|200px]]
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|align="center"|
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[[Image:Purplecuprian.jpg|200px]]
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|-
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|width="33%" align="center"|Mozambique "Paraiba-type" tourmaline 3.71 ct <br />Photo courtesy of Precision Gem
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|width="33%" align="center"|Nigerian "Paraiba-type" tourmaline, 1.53 ct <br />Photo by Jeff Scovil<br /> Courtesy of R.W. Wise Goldsmiths
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|width="34%" align="center"|Mozambique "Paraiba-type" tourmaline, 8.14 ct, unheated.<br />Photo by Jeff Scovil.<br />Courtesy of R.W. Wise Goldsmiths
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|}

Latest revision as of 05:54, 21 June 2007

Paraiba Tourmaline
Chemical composition Complex borosilicate
Crystal system Trigonal
Habit Prismatic
Cleavage None
Fracture Conchoidal
Hardness 7.5
Optic nature Uniaxial -
Refractive index 1.62 - 1.64
Birefringence 0.014 - 0.022
Dispersion Low, 0.018
Specific gravity 3.06
Lustre Vitreous
Pleochroism Weak to strong
Brazilian Paraiba tourmaline
Photo courtesy of Lembeck Gems

Paraiba type

Mozparaiba.jpg

6403 d.jpg

Purplecuprian.jpg

Mozambique "Paraiba-type" tourmaline 3.71 ct
Photo courtesy of Precision Gem
Nigerian "Paraiba-type" tourmaline, 1.53 ct
Photo by Jeff Scovil
Courtesy of R.W. Wise Goldsmiths
Mozambique "Paraiba-type" tourmaline, 8.14 ct, unheated.
Photo by Jeff Scovil.
Courtesy of R.W. Wise Goldsmiths