mineral

Sphalerite in Matrix (Polished Point)

Zinc sulfide (Zn,Fe)S

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.

Hardness: 3
Luster: Adamantine to resinous

Identified May 10, 2026More mineral →

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Physical properties

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.

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