Banded Sphalerite - Natural minerals and crystals

Schalenblende is a variety of sphalerite (zinc sulphide, ZnS) displaying a characteristic concentric structure, formed of alternating layers of sphalerite, wurtzite, galena and marcasite. Its name, of German origin, literally means "shell blende", referring to this banded structure reminiscent of strata or growth rings. This distinctive texture results from successive colloidal deposition within rock cavities, creating unique concentric patterns visible to the naked eye, often in shades ranging from metallic grey to brown, with yellowish tones in between. From a crystallographic standpoint, Schalenblende belongs to the cubic system, although its growth in spherical or botryoidal aggregates often conceals this symmetry. Its hardness ranges between 3.5 and 4 on the Mohs scale, and its density is around 4 g/cm³. This mineral forms mainly in low-temperature hydrothermal deposits, typically associated with lead-zinc ore bodies. Prized by collectors and geologists for its singular aesthetic, Schalenblende is a remarkable example of rhythmic banded mineralisation, a phenomenon studied in petrography to understand sequential precipitation processes.

25 produits