Spinel

Color: Red, purple, blue, lavender, green, pink, yellow (unusual), orange/peach

Moh’s Hardness: 8

Refractive Index: 1.712-1.736

Critical Angle: 35.79°

Specific Gravity: 3.58-3.61

Cleavage: Imperfect

Fracture: Conchoidal, uneven

Dispersion: Moderately high (.026)

Heat Sensitivity: None

Birefringence (double refraction): None

Crystal Structure: Isometric

Treatments: Generally none