The mineral Sphalerite is the main ore for obtaining zinc. Its main content, zinc sulfide is in the form of crystals, but always includes variable amounts of iron. In the event of high iron content, it leads to the formation of an opaque variety called Magnetite.
(Zn, Fe) S
Derivation of Name
Georgius Agricola (Georg Bauer) initially named it as Blende in 1546. Ernst Friedrich Glocker gave it its current name in 1847, deriving it from Greek σφαλεροζ or "sphaleros", meaning deceitful, as its darker varieties could easily be misunderstood as Galena, but failed to offer any lead. After Acricola but before Glocker, it was known by different names, based on its chemistry. “Zincum” was among those names.
All over the world, there are many places where this zinc ore is found. It is typically found along with Pyrite, Galena plus other sulfides in the company of Dolomite, Fluorite and Calcite. It is understood that miners used the words Black Jack, zinc Blende plus Ruby Jack, when referring to Sphalerite
Appropriately sized and transparent crystals have been shaped to gemstones. The brilliant cut is generally exploited to best demonstrates a 0.156 B to G dispersal., which is thrice that of diamond. Newly cut gems possess an Adamantine Patina. The color of the gem quality mineral usually varies from orange to red, yellowish to honey brown and green.
Sources of superior crystals are:
- Saxony, Freiberg, and Neudorf, in Germany’s Harz Mountains
- Pribramnand Horni Slavkov in Schlaggenwaldm in the Czech Republic
- Transparent opaque to green crystals from Bulgaria’s Rhodope Mountains
- Colorless crystals came from the famous Lengenbach Quarry, in Switzerland
- Clear crystals at the Aliva mine in the Mountains of Picos de Europa in Cantabria Province of Spain
- From Rodna, Romania
- Dalnegorsk, Russia
- Alston Moor in Cumbria. England
The mineral forms crystals in a cubic crystal arrangement. Sulfur and zinc atoms get tetrahedrally coordinated in the structure of crystals. This structure is very much correlated to that of the diamond structure. The “Wurtzite structure” is the name of the hexagonal analog. Zinc Sulfide’s lattice constant in the zinc Blende crystal structure reads NM 0.541, calculated from the geometry plus the ionic radii, NM 0.184 (sulfide) and NM 0.074, (zinc). It forms layers of ABCABC.
Brown, red, green, yellow and black
Mohs scale hardness
3.5 to 4