DIOPSIDE

This black star diopside has 4 rays

Species:  Diopside
Mohs Hardness:  8.5 out of 10
Color:  Bluish green to yellowish green, gray or black.  Chrome diopside is an intense green.
RI:  1.675 to 1.701 (+ 0.029 / - 0.010)
Birefringence:  0.024 to 0.030
SR/DR/AGG:  DR
Clarity Type:  Type II
Optic Character:  Biaxial positive
Pleochroism:  Weak to strong light and dark green
Spectrum:  Varies
Fluorescence:  Green under LW, inert under SW
SG:  3.29 (+0.11 / -0.07)

Diopside Facts

Natural star diopside before/after flashbulb [Photo courtesy of Scott Papper, GIA GG, AJP, CMA (NAJA)]

Two forms of diopside are usually found in jewelry:  chrome diopside and star diopside.

Chrome diopside can have an intense green color.

Star diopside displays a rare phenomena known as asterism:  many intersecting needle inclusions that scatter light, causing a 4-rayed star.

All photos courtesy of Scott Papper, GG, ASA, CMA, RGA, AJP, CMSP, CSSP