Fire+Opal

Category: Mineraloid

Formula: Hydrated Silica Sio2.nH2O

Color: clear, white, yellow, red, orange, free, brown, black, blue

Hardness: 5.5-6

Density: 2.09

Crystal System: Amorphous

Streak: White

Luster: Subvitreous to waxy

optical properties: single refractive, often anomalous double refractive due to strain

Cited from wikipedia

By: Max Boonstra and Simon Park