Sphalerite is the chief ore of zinc. It consists largely of zinc sulfide in crystalline form but almost always contains variable iron. When iron content is high it is an opaque black variety, marmatite. It is usually found in association with galena, pyrite, and other sulfides along with calcite, dolomite, and fluorite. Miners have also been known to refer to sphalerite as zinc blende, black-jack, and ruby jack.
Very Large Sphalerite—A Member of the 100 Carats Club Picos de Europa, Santander, Spain From a very small mine, now closed for at least twenty years, comes this superb and rare faceted sphalerite. Sphalerite, a zinc iron sulfide, is usually found in black and very rarely in the rich orange color seen here—and it is rarely seen cut into a gemstone. The luster of sphalerite is its strongest attribute, i.e. it is adamantine, with a high refractive index and brilliance greater than diamonds.
DIY Night Bike. From Instructables here. The trick is the type of paint chosen to paint the bike: “The typical craft store glow paint is zinc-sulfide based in an acrylic medium, if it is colored pigments are used. The problem with using pigments is that these colors absorb most of the light, and thus the glow isn’t as bright. Instead, phosphorescent paint (used for this bike) is strontium based and glows 10 times longer and brighter. Impressive!"
Zinc sulfide - Mixtures of zinc and sulfur react pyrotechnically, leaving behind zinc sulfide - Zinc sulfide (or zinc sulphide) is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite. Although this mineral is usually black because of various impurities, the pure material is white, and it is widely used as a pigment.