Opal

Introduction: Opal occurs in many colours and can be cut and polished. It is chemically similar to quartz but with the addition of water and is common in the vicinity of the vents of hot springs and in gossans.

Distribution: Pegmatites in the Erongo Mountains and opalized and silicified wood is found at the Petrified Forest in the Khorixas District.

Composition: Silicate

Crystal system: Amorphous

Lustre: Resinous, waxy, vitreous, pearly

Streak: White

Hardness: 5.5-6.5