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Untreated spinel
Untreated spinel
Formula MgAl2O4
Molecular mass 142.27 g/mol
admixture Ti,Fe,Zn,Mn,Ca
IMA Status Valid
Systematics according to IMA (Mills et al., 2009)
Class Oxides and hydroxides
Group Aluminospinels
Physical properties
Color Colorless, red, pink, blue, green, purple, yellow
Dash color grayish white
Shine Glass
Transparency Transparent to translucent
Mohs hardness 7.5 – 8
fragility Fragile
Cleavage imperfect
kink conchoidal
Density 3.57-3.72 g/cm³
Crystallographic properties
space group Fd3m
Syngony cubic
Optical properties
optical type isotropic
Refractive index 1.71-1.76
Birefringence Missing
optical relief High
Dispersion of optical axes 0.026
Pleochroism Visible
Luminescence From none to strong (under LW). In red – strong, red (LW, SW); blue has a weak reddish or green (LW, SW); green-weak reddish (LW)

Strode Anna

Anna Strod – director of the jewelry online store Author and editor of the jewelry blog

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