sedimentary
African Turquoise (Jasper)
Impure variety of silica, primarily Quartz (SiO2) with various inclusions
Hardness: 6.5-7 (Mohs scale), Color: Teal and green with black and brown mottling, Luster: Vitreous to waxy, Crystal Structure: Microcrystalline (trigonal), Cleavage: None, Specific Gravity: 2.5–2.9
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Teal and green with black and brown mottling, Luster: Vitreous to waxy, Crystal Structure: Microcrystalline (trigonal), Cleavage: None, Specific Gravity: 2.5–2.9
Formation & geological history
Formed through the accumulation of volcanic ash or silica-rich sediments that undergo high-pressure silicification, resulting in a dense, opaque microcrystalline quartz. Most modern specimens originate from mines in Africa.
Uses & applications
Primarily used for beads, cabochons, and jewelry. It is a popular affordable substitute for traditional turquoise in bohemian and artisanal crafts.
Geological facts
Despite its name, African Turquoise is actually a type of Jasper, not a true turquoise. It is much harder and more durable than true turquoise, which is a phosphate mineral.
Field identification & locations
Identify by its distinct greenish-teal base color and heavy presence of dark matrix spots (often iron or manganese). It is common in gem shows and craft stores. To distinguish from real turquoise, check hardness; Jasper will not scratch easily with steel.
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