mineral
Sphalerite in Matrix (Polished Point)
Zinc sulfide (Zn,Fe)S
AI-generated identification · may be incorrectHardness: 3.5-4 (Mohs); Color: dark brown to black (sub-metallic) with white/grey calcite or quartz matrix; Luster: Adamantine to resinous; Crystal structure: Isometric/Cubic; Cleavage: Perfect in six directions.
- Hardness
- 3
- Luster
- Adamantine to resinous
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Physical properties
Hardness: 3.5-4 (Mohs); Color: dark brown to black (sub-metallic) with white/grey calcite or quartz matrix; Luster: Adamantine to resinous; Crystal structure: Isometric/Cubic; Cleavage: Perfect in six directions.
Formation & geological history
Formed in low to medium-temperature hydrothermal veins, often found in carbonate rocks through replacement processes. These specimens are frequently sourced from deposits in locations like Missouri (USA), Spain, or Bulgaria.
Uses & applications
Primary ore of zinc; used in the production of brass, galvanized steel, and batteries. Polished towers (points) are popular for crystal collecting, home decor, and metaphysical practices.
Geological facts
Sphalerite is often called 'Black-Jack' by miners due to its dark, lustrous appearance. It is a major ore mineral but is rarely used as a gemstone because it is too soft for daily jewelry wear.
Field identification & locations
Identify by its resinous luster and streak color (pale yellow to brown). In the field, look for its association with galena, calcite, and fluorite. Polished points are shaped artificially to show off internal patterns.
