Archive for the Spinel Group Category

  • Spinel – Synthetic

    Refractive Index : 1.728 (+0.012 – 0.008)

    Optical Characteristic : SR, ADR

    Specific Gravity : 3.64 (+0.02 – 0.12)

    Formula : MgAI2O4

    Crystal System : Cubic

    Variety/Species : All

    Species/Group : Synthetic spinel

    Birefringence : none

    Dispersion : .020

    Hardness : 8

    Toughness : good

    Ultrasonic : Usually safe

    Steam : usually safe

    UV Long : Inert to strong

    UV Short : Inert to strong

    Pleochroism : None

    Strength : N/A

    Pleochroism [...]

  • Spinel

    Natural Spinel Gemstone

    Refractive Index : 1.718 (+0.017 – 0.008)

    Optical Characteristic : SR

    Specific Gravity : 3.60 (+0.10 – 0.03)

    Formula : MgAI2O4

    Crystal System : Cubic

    Variety/Species : Spinel

    Species/Group : Spinel Group

    Birefringence : none

    Dispersion : 0.020

    Hardness : 8

    Toughness : good

    Ultrasonic : Usually safe

    Steam : usually safe

    UV Long : Red, orange and pink : Inert to weak red to [...]