Tourmaline Crystals- 5.08 g
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Description from the seller
25 carats faceted rough tourmaline
Origin kunar Afghanistan
Untreated and unheated
Faceted rough quality
Open colour
Good clarity (eye clean pieces)
Characteristic of Tourmaline
Chemical composition: Complex borosilicate of aluminium with varying amounts of iron, magnesium, lithium, sodium, calcium, and other elements
Crystal system: Trigonal
Hardness: 7–7.5 on the Mohs scale
Specific gravity: 3.00–3.26
Refractive index: 1.614–1.666
Birefringence: 0.014–0.040
Luster: Vitreous
Transparency: Transparent to opaque
Cleavage: Indistinct to poor
Fracture: Uneven to subconchoidal
Dispersion: 0.017–0.020
Pleochroism: Strong, especially in colored varieties
Common colors: Colorless, pink, red, green, blue, yellow, brown, black, violet, and multicolored (bicolor and watermelon)
Fluorescence: Usually inert, though some pink and red tourmalines may show weak fluorescence
Inclusions: Hollow tubes, liquid inclusions, growth tubes, fingerprints, healed fractures, and mineral crystals
Common treatments: Heat treatment is common; irradiation is less common
Major sources: Pakistan, Afghanistan, Brazil, Nigeria, Mozambique, Madagascar, Namibia, Sri Lanka, Tanzania, and the United States
25 carats faceted rough tourmaline
Origin kunar Afghanistan
Untreated and unheated
Faceted rough quality
Open colour
Good clarity (eye clean pieces)
Characteristic of Tourmaline
Chemical composition: Complex borosilicate of aluminium with varying amounts of iron, magnesium, lithium, sodium, calcium, and other elements
Crystal system: Trigonal
Hardness: 7–7.5 on the Mohs scale
Specific gravity: 3.00–3.26
Refractive index: 1.614–1.666
Birefringence: 0.014–0.040
Luster: Vitreous
Transparency: Transparent to opaque
Cleavage: Indistinct to poor
Fracture: Uneven to subconchoidal
Dispersion: 0.017–0.020
Pleochroism: Strong, especially in colored varieties
Common colors: Colorless, pink, red, green, blue, yellow, brown, black, violet, and multicolored (bicolor and watermelon)
Fluorescence: Usually inert, though some pink and red tourmalines may show weak fluorescence
Inclusions: Hollow tubes, liquid inclusions, growth tubes, fingerprints, healed fractures, and mineral crystals
Common treatments: Heat treatment is common; irradiation is less common
Major sources: Pakistan, Afghanistan, Brazil, Nigeria, Mozambique, Madagascar, Namibia, Sri Lanka, Tanzania, and the United States
Details
Main mineral
Tourmaline
Mineral form
Crystals
Weight
5.08 g
Origin (region/city)
Kunar
Country of origin
Afghanistan
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