Spinel synthetic Verneuil
Refractive Index
1.723 - 1.740
Density
3.60 - 3.78
Polariscope
iso
Colours:
colourless, yellow, blue, pink, red, violet, orange, green, purple
Transparency:
Transparent
UVL:
pale blue stones: red to orange red; pale blue-green stones: yellow, pink and yellow-green stones: green
UVS:
white greenish or colour stronger than UVL
Remarks:
inclusions: gas bubbles, rarely curved growth lines, distinct anomalous birefrigence (undulatory extinction, TABY EXTINCION, RI>1.72, strong UV reaction
rarely adularescent
transparency:= opaque: lapis lazuli-like
Hardness:
8 - 8
Formula:
MgAI2O8
System:
Cubic
Rare?
1