Archive for the Species Category
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Refractive Index : 1.553 – 1.544
Optical Characteristic : DR, U+, AGG
Specific Gravity : 2.651 (+0.04 – 0.01)
Formula : SiO2
Crystal System : Trigonal
Variety/Species : smoky
Species/Group : Quartz
Birefringence : 0.009
Dispersion : 0.013
Hardness : 7
Toughness : good
Ultrasonic : Usually safe
Steam : risky
UV Long : Inert
UV Short : Inert
Pleochroism : 2 colors
Strength : weak
Pleochroism Colors : Dark stones, weak: [...]
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Refractive Index : 1.770 – 1.762 (+0.009 – 0.005)
Optical Characteristic : DR U-, AGG
Specific Gravity : 4.00 (+0.10 – 0.05)
Formula : AI2O3
Crystal System : Trigonal
Variety/Species : Sapphire
Species/Group : Corundum
Birefringence : 0.008 to 0.010
Dispersion : 0.018
Hardness : 9
Toughness : Good to excellent
Ultrasonic : Usually safe
Steam : usually safe
UV Long : Inert to strong
UV Short : Inert [...]
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Refractive Index : 1.553-1.554
Optical Characteristic : DR, AGG
Specific Gravity : 2.651 +.06 -.01
Formula : SiO2
Crystal System : Trigonal
Variety/Species : Tiger’s Eye
Species/Group : Quartz
Birefringence : 0.009
Dispersion : N/A
Hardness : 7
Toughness : Good
Ultrasonic : Uaually safe
Steam : Risky
UV Long : Inert
UV Short : Inert
Pleochroism : None
Strength : N/A
Pleochroism Colors : None
Heat : Avoid aburt temperature change
Acids : [...]
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Refractive Index : 1.583-1.577 + 0.017 – 0.017
Optical Characteristic : DR, U-
Specific Gravity : 2.72 + 0.18 – 0.05
Formula : Be3AI2Si6O18
Crystal System : Hexagonal
Variety/Species : Trapiche emerald
Species/Group : Beryl
Birefringence : 0.005 to 0.009
Dispersion : 0.014
Hardness : 7.5 to 8
Toughness : Poor to good
Ultrasonic : Never
Steam : Never
UV Long : Inert to strong
UV Short : Inert [...]
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Refractive Index : 1.676 – 1.660 + 0.005 – 0.005
Optical Characteristic : DR B+
Specific Gravity : 3.18 + 0.03 – 0.03
Formula : LiAISi2O6
Crystal System : Monoclinic
Variety/Species : Spodumene
Species/Group : Pyroxene group
Birefringence : 0.014 to0.016
Dispersion : 0.017
Hardness : 6.5 to 7
Toughness : Poor
Ultrasonic : Never
Steam : Never
UV Long : Inert to moderate
UV Short : Inert to [...]
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Refractive Index : 1.54 – 1.53
Optical Characteristic : AGG
Specific Gravity : 2.60 + 0.30 – 0.05
Formula : SiO2
Crystal System : Trigonal
Variety/Species : Chalcedony
Species/Group : Cryptocrystaline Quartz
Birefringence : 0.004
Dispersion : None
Hardness : 6.5 to 7
Toughness : Good
Ultrasonic : Uaually safe
Steam : Usually safe
UV Long : Inert to moderate
UV Short : Inert to moderate
Pleochroism : None
Strength : [...]
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Refractive Index : 1.583 – 1.577 (+0.017 – 0.017)
Optical Characteristic : DR U-
Specific Gravity : 2.72 (+0.18 – 0.05)
Formula : Be3AI2Si6O18
Crystal System : Hexagonal
Variety/Species : Emerald
Species/Group : Beryl
Birefringence : 0.005 to .009
Dispersion : 0.014
Hardness : 7.5 to 8
Toughness : Poor to good
Ultrasonic : Never
Steam : Never
UV Long : Inert to strong
UV Short : Inert to [...]
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Refractive Index : 1.786 – 1.729
Optical Characteristic : DR, uniaxial negative
Specific Gravity : 3.32
Formula : NaMg3V6(Si6O18)(BO3)3(OH)4
Crystal System : Trigonal
Variety/Species : Tourmaline
Species/Group : Tourmaline Group
Birefringence : 0.057
Dispersion : 0.017
Hardness : 7.5
Toughness : Fair
Ultrasonic : Risky
Steam : Risky
UV Long : Inert
UV Short : Inert
Pleochroism : 2 colors
Strength : Moderate to strong
Pleochroism Colors : No data
Heat : May [...]
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Refractive Index : 1.590 – 1.560 (+ 0.003 – 0.006)
Optical Characteristic : DR, AGG
Specific Gravity : 2.50 (- 0.10 + 0.10)
Formula : AIPO4.2(H2O)
Crystal System : Orthorhombic
Variety/Species : All
Species/Group : Variscite
Birefringence : Not detectable
Dispersion : N/A
Hardness : 3.5 to 5
Toughness : Poor
Ultrasonic : Never
Steam : Never
UV Long : Inert to weak
UV Short : Inert to weak
Pleochroism : [...]
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Refractive Index : 1.643 – 1.634 (+ 0.005 – 0.005)
Optical Characteristic : DR, Biaxial negative, AGG
Specific Gravity : 3.17 + 0.04 – 0.04
Formula : AI2SiO5=AI[6]A[5]OSiO4
Crystal System : Orthorhombic
Variety/Species : Andalusite
Species/Group : Andalusite
Birefringence : 0.007 – 0.003
Dispersion : 0.016
Hardness : 7 to 7.5
Toughness : Fair to good
Ultrasonic : Uaually safe
Steam : Risky
UV Long : Inert
UV Short [...]
