Archive for the Orthorhombic Category

  • Star Enstatite

    Refractive Index : 1.673 – 1.663 (+0.010 – 0.010)

    Optical Characteristic : DR, B+

    Specific Gravity : 3.25 (+0.15 – 0.02)

    Formula : MgSiO3

    Crystal System : Orthorhombic

    Variety/Species : Enstatite

    Species/Group : Pyroxene group

    Birefringence : 0.008 to 0.011

    Dispersion : none

    Hardness : 5 to 6

    Toughness : poor

    Ultrasonic : risky

    Steam : Never

    UV Long : Inert

    UV Short : Inert

    Pleochroism : 2 or 3 [...]

  • Stibiotantalite

    Refractive Index : 2.460 – 2.370

    Optical Characteristic : DR, B+

    Specific Gravity : 7.46 – 7.34

    Formula : SbTaO4

    Crystal System : Orthorhombic

    Variety/Species : All

    Species/Group : stibiotantalite

    Birefringence : 0.090

    Dispersion : 0.146

    Hardness : 5 to 5.5

    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 [...]

  • Strontianite

    Refractive Index : 1.670 – 1.520

    Optical Characteristic : DR, B-, AGG

    Specific Gravity : 3.785 – 3.630

    Formula : SrCO3

    Crystal System : Orthorhombic

    Variety/Species : strontianite

    Species/Group : Aragonite Group

    Birefringence : 0.150

    Dispersion : 0.008 – 0.028

    Hardness : 3.5

    Toughness : Fair to poor

    Ultrasonic : Never

    Steam : Never

    UV Long : Inert to moderate

    UV Short : Inert to moderate

    Pleochroism : None

    Strength : [...]

  • Tantalite

    Refractive Index : 2.430 – 2.260

    Optical Characteristic : DR, B+

    Specific Gravity : 8.2 – 5.5

    Formula : MnTa2O6

    Crystal System : Orthorhombic

    Variety/Species : All

    Species/Group : Tantalite

    Birefringence : 0.160

    Dispersion : N/A

    Hardness : 6 to 6.5

    Toughness : poor

    Ultrasonic : Never

    Steam : Never

    UV Long : Inert

    UV Short : Inert

    Pleochroism : 3 colors

    Strength : weak to moderate

    Pleochroism Colors : Strong: Brown/red-brown.

    Heat [...]

  • Tephroite

    Refractive Index : 1.825 – 1.770

    Optical Characteristic : DR, B-, AGG

    Specific Gravity : 4.11

    Formula : Mn2SiO4

    Crystal System : Orthorhombic

    Variety/Species : All

    Species/Group : Tephroite

    Birefringence : 0.037 – 0.047

    Dispersion :

    Hardness : 6

    Toughness : poor

    Ultrasonic : Never

    Steam : Never

    UV Long : Inert

    UV Short : Inert

    Pleochroism : 3 colors

    Strength : weak to moderate

    Pleochroism Colors : Moderate: Greenish blue/ [...]

  • Thomsonite

    Refractive Index : 1.540 – 1.515 (+0.015 – 0.018)

    Optical Characteristic : DR, B+ , AGG

    Specific Gravity : 2.35 (+0.05 – 0.10)

    Formula : NaCa2AI5Si5O20.6(H2O)

    Crystal System : Orthorhombic

    Variety/Species : Thomsonite

    Species/Group : Zeolite Group

    Birefringence : 0.021

    Dispersion : N/A

    Hardness : 5 to 5.5

    Toughness : Fair

    Ultrasonic : Never

    Steam : Never

    UV Long : Inert to moderate

    UV Short : Inert

    Pleochroism : None

    Strength [...]

  • Thulite

    Refractive Index : 1.701-1.695

    Optical Characteristic : DR, B+, AGG

    Specific Gravity : 3.09

    Formula : Ca2AI3(SiO4)3(OH)=Ca2AIAI1(SiO4)(Si2O7)O(OH)

    Crystal System : Orthorhombic

    Variety/Species : Zoisite

    Species/Group : Epidote Group

    Birefringence : 0.006

    Dispersion : 0.021

    Hardness : 6 to 7

    Toughness : Fair to poor

    Ultrasonic : Uaually safe

    Steam : Usually safe

    UV Long : Inert

    UV Short : Inert

    Pleochroism : 3 Colors

    Strength : Weak to moderate

    Pleochroism Colors : Weak [...]

  • Shattuckite

    Refractive Index : 1.815 – 1.75 spot 1.75

    Optical Characteristic : AGG

    Specific Gravity : 3.80 (+0.34 – 1.27)

    Formula : Cu5(SiO3)4(OH)2.

    Crystal System : Orthorhombic

    Variety/Species : All

    Species/Group : Shattuckite

    Birefringence : 0.063

    Dispersion : none

    Hardness : 3.5 to 4

    Toughness : poor

    Ultrasonic : Never

    Steam : risky

    UV Long : Inert

    UV Short : Inert

    Pleochroism : None

    Strength : N/A

    Pleochroism Colors : None

    Heat : unknown

    Acids [...]

  • Sulfur

    Refractive Index : 2.245 – 1.958

    Optical Characteristic : DR, B+

    Specific Gravity : 2.09 – 2.05

    Formula : S8

    Crystal System : Orthorhombic

    Variety/Species : All

    Species/Group : Sulfur

    Birefringence : 0.291

    Dispersion : 0.155

    Hardness : 1.5 to 2.5

    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 [...]

  • Variscite

     

    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 : [...]