Archive for the Hexagonal Category

  • Star Beryl

    Refractive Index : 1.583 – 1.577 (+0.017 – 0.017)

    Optical Characteristic : DR, U-

    Specific Gravity : 2.72 (+0.18 – 0.05)

    Formula : Be3Al2Si6O18

    Crystal System : Hexagonal

    Variety/Species : Star Beryl

    Species/Group : Beryl

    Birefringence : 0.005 – 0.009

    Dispersion : 0.014

    Hardness : 7.5 to 8

    Toughness : good

    Ultrasonic : risky

    Steam : risky

    UV Long : Inert

    UV Short : Inert

    Pleochroism : 2 colors

    Strength : [...]

  • Sogdianite

    Refractive Index : 1608 – 1.606

    Optical Characteristic : DR, U-

    Specific Gravity : 2.90 – 2.76

    Formula : (K,Na)2Li,Fe,AI,Ti)2Zr2(Si2O5)6

    Crystal System : Hexagonal

    Variety/Species : sogdianite

    Species/Group : Osumilite group

    Birefringence : 0.002

    Dispersion :

    Hardness : 5 to 7

    Toughness : poor

    Ultrasonic : Never

    Steam : Never

    UV Long : Inert to weak

    UV Short : Inert to weak

    Pleochroism : None

    Strength : N/A

    Pleochroism Colors : [...]

  • Taafeite

    Refractive Index : 1.723 – 1.719 (+0.002 – 0.002)

    Optical Characteristic : DR, U-

    Specific Gravity : 3.61 (+0.01 – 0.01)

    Formula : BeMg3AI8O16 + Fe, Mn, Zn, V, Cr.

    Crystal System : Hexagonal

    Variety/Species : All

    Species/Group : Taafeite

    Birefringence : 0.004 to 0.005

    Dispersion : 0.019

    Hardness : 8 to 8.5

    Toughness : good

    Ultrasonic : risky

    Steam : risky

    UV Long : Inert to weak

    UV [...]

  • Thaumasite

    Refractive Index : 1.507-1.464

    Optical Characteristic : DR, U-

    Specific Gravity : 1.91

    Formula : Ca38i(CO3)(804)(OH)6.12(H2O)

    Crystal System : Hexagonal

    Variety/Species : All

    Species/Group : Thaumasite

    Birefringence : .036

    Dispersion : none

    Hardness : 3.5

    Toughness : poor

    Ultrasonic : Never

    Steam : Never

    UV Long : Inert

    UV Short : Inert to moderate

    Pleochroism : None

    Strength : N/A

    Pleochroism Colors : None

    Heat : sensitive

    Acids : sensitive

    Light : stable

    Polish Luster : [...]

  • Sugilite

    Refractive Index : 1.610 – 1.607 (+0.001 – 0.002)

    Optical Characteristic : DR U-, AGG

    Specific Gravity : 2.74 (+0.05)

    Formula : (K,Na)(Na,Fe+3)2(Li2,Fe+3)Si12O30 + Mn.

    Crystal System : Hexagonal

    Variety/Species : Sugilite

    Species/Group : Osumilite group

    Birefringence : None to 0.003

    Dispersion : N/A

    Hardness : 5.5 to 6.5

    Toughness : good

    Ultrasonic : risky

    Steam : risky

    UV Long : Inert

    UV Short : Inert

    Pleochroism : None

    Strength : [...]

  • Trapiche Emerald

    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 [...]

  • Emerald

    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 [...]

  • Algodonite

     

    Refractive Index : 0.00

    Optical Characteristic : DR, Uniaxial, Agg

    Specific Gravity : 8.38 – 7.92

    Formula : Cu6As

    Crystal System : Hexagonal

    Variety/Species : All

    Species/Group : Algodonite

    Birefringence :

    Dispersion :

    Hardness : 3 to 4

    Toughness : Poor

    Ultrasonic : Never

    Steam : Never

    UV Long : Inert

    UV Short : Inert

    Pleochroism : None

    Strength : N/A

    Pleochroism Colors : None

    Heat : Sensitive

    Acids : Sensitive

    Light : [...]

  • Vanadinite

     

    Refractive Index : 2.416 – 2.350

    Optical Characteristic : DR, Uniaxial negative

    Specific Gravity : 7.10 – 6.80

    Formula : Pb5(VO4)3CI

    Crystal System : Hexagonal

    Variety/Species : Vanadinite

    Species/Group : Apatite Group

    Birefringence : 0.066

    Dispersion : 0.202

    Hardness : 3.5 to 4

    Toughness : Poor

    Ultrasonic : Never

    Steam : Never

    UV Long : Inert

    UV Short : Inert

    Pleochroism : 2 colors

    Strength : weak

    Pleochroism Colors : Very weak [...]