African Turquoise (Jasper)

Hardness: 6.5-7 on Mohs scale (for jasper). Color: Ranges from greenish-blue to teal, often with dark matrix inclusions (speckles and veins of brown, black, or grey minerals). Luster: Dull to vitreous (glassy) when polished. Crystal Structure: Microcrystalline quartz, so no visible crystals. Cleavage: None, exhibits conchoidal fracture. Specific Gravity: 2.58-2.64.

Formation Process: Jasper is a form of chalcedony, which is microcrystalline quartz. It forms as silica-rich sediments are deposited from hot solutions, often in volcanic environments or as primary deposits. The distinctive coloration and patterning in African Turquoise (Jasper) arise from the presence of various mineral inclusions and impurities during its formation, such as iron oxides and other metallic minerals. Geological Age: Varies, but many jasper deposits are associated with ancient volcanic activity and can range from Precambrian to Cenozoic.

Uses: Primarily used in jewelry for beads, cabochons, and carvings due to its attractive color and patterns. It is also used in ornamental objects and decorative items. Its appealing visual characteristics make it popular in crafting and lapidary arts. Collecting Value: Valued for its aesthetic appeal, especially pieces with interesting matrix patterns or vibrant teal colors. It is generally an affordable gemstone.

Interesting Facts: Despite its common market name 'African Turquoise,' this stone is actually a type of jasper. The name 'African Turquoise' is a trade name used to describe its appearance, which can resemble genuine turquoise, especially due to its greenish-blue hue and matrix. However, it lacks the chemical composition and geological formation of true turquoise (a hydrated copper aluminum phosphate). It often displays a mottled or speckled appearance, which makes each piece unique.

How to Identify in the Field: As a polished bead, direct field identification is difficult. However, raw African Jasper would typically be found in masses or nodules within host rocks, often associated with volcanic or sedimentary formations. Its characteristic greenish-blue color with dark inclusions is a key visual identifier. Common Locations Found: Primarily sourced from Africa, particularly in various regions. Specific mining locations are often proprietary information of suppliers, but general regions in Africa are known for producing this type of jasper. Tips for Collectors: Look for vibrant colors and interesting matrix patterns. Be aware of the distinction between 'African Turquoise' (jasper) and true turquoise. It is a durable stone suitable for everyday wear.