red, pink, bluish violet to greenish blue, purple, lavender, blue, bluish-green, brown, black, colorless, green, orange, yellow
flame spinel, rubicelle, ceylonite, pleonaste
refractive index, SR nature, magnification and spectrum. An accurate RI reading can distinguish natural from synthetic spinel, which usually has a higher RI. Red spinel often shows a chromium spectrum with lines in the red, possibly as emission lines.
Spinel frequently occurs in an octahedral form with triangular etch pits on the faces. Also appears in a flat twinned form as a macle.Flame spinel or rubicelle: orange, orange-red to yellowish red spinel usually from Brazilceylonite: dingy blue, gray to black with no iron contentpleonaste: opaque very dark blue or green to black containing ironMisnomers: Balas ruby, spinel ruby, almandine spinel, sapphire spinel, sapphirine Blue and red spinel tends to be on the higher side of the RI limit.