May 8 2013
Sphalerite is also referred to as Blende or Zinc Blende, and is the major ore of zinc. Sphalerite got its name from the Greek word ‘sphaleros’ which means treacherous, as it was first mistaken for the lead ore galena.
Properties of Sphalerite
The following are the key properties of sphalerite:
- Cell Data
- Space group: F43m
- a = 5.4060
- Z = 4
- Crystal Data
- Cubic
- Point group: 43m
- Crystals -tetrahedral, dodecahedral, typically complex and distorted, curved and conical faces common, to 30 cm. They are also fibrous, botryoidal, stalactitic, cleavable, coarse to fine granular and massive
- Twinning: Twin axis [111], twin plane {111}, simple contact twins or complex lamellar forms
- X-ray powder pattern: 3.123 (100), 1.912 (51), 1.561 (30), 2.705 (10), 1.240 (9), 1.1034 (9), 1.351 (6)
- Chemical Composition
| Elements |
Content 1 |
Content 2 |
Content 3 |
| Zn |
66.98 |
44.67 |
67.10 |
| S |
32.78 |
33.57 |
32.90 |
| Fe |
0.15 |
18.25 |
- |
| Mn |
- |
2.66 |
- |
| Cd |
- |
0.28 |
- |
| Total |
99.91 |
99.43 |
100.00 |
- Optical Properties
- Optical class: Isotropic
- n = 2.369 (Na) (ZnS)
- Anisotropism: May show strain-induced birefringence
- R: (400) 19.6, (420) 19.0, (440) 18.3, (460) 17.9, (480) 17.5, (500) 17.2, (520) 16.9, (540) 16.7, (560) 16.5, (580) 16.4, (600) 16.3, (620) 16.2, (640) 16.1, (660) 16.0, (680) 15.9, (700) 15.8
- Estimated Properties
| Electron density |
Bulk density (electron density)= 3.85 g/cm3
note: Specific gravity of sphalerite = 4.08 g/cm3 |
| Photoelectric |
PESphalerite = 35.10 barns/electron
U=PESphalerite x ρelectron density= 135.25 barns/cm3 |
| Fermion index |
Fermion index = 0.02
Boson index = 0.98 |
Radioactivity
|
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Sphalerite is not radioactive |
How to Identify Sphalerite
Sphalerite can be identified in the field by its brown, yellow, red, green and black color variations. The appearance of this mineral is translucent to transparent. It is a mineral with a resinous-greasy luster, a brownish white streak, and cleavages. The fractures in the mineral are uneven. The crystals are euhedral and granular. The density of sphalerite is 3.9-4.2 g/cm3 and hardness is 3.5 - 4 – between copper penny and fluorite.
Global Distribution
Sphalerite is widely distributed, and good examples can be found in the following locations:
- England - From Alston Moor, Cumbria
- Germany - From Freiberg, Saxony, and Neudorf, Harz Mountains
- Czech Republic - At HornL. Slavkov(Schlaggenwald) and P.r L.bram
- Romania - From Rodna
- Canada - From Watson Lake, Yukon Territory
- Spain - Transparent crystals in the Aliva mine, Picos de Europa Mountains, Cantabria [Santander] Province
- Switzerland - Colorless crystals in the Lengenbach quarry, Binntal, Valais
- Russia - At Dalfnegorsk, Primorskiy Kray
- USA - In the Tri-State district of the Mississippi Valley; near Baxter Springs, Cherokee Co., Kansas; Joplin, Jasper Co., Missouri and Picher, Ottawa Co., Oklahoma. From the Elmwood mine, near Carthage, Smith Co., Tennessee; in the Eagle mine, Gilman district, Eagle Co., Colorado
- Peru - At Huaron, Casapalca, and Huancavelica
- Mexico - from Santa Eulalia and Naica, Chihuahua, and Cananea, Sonora.
Occurrence of Sphalerite and Useful Mineral Association
Sphalerite is often associated with minerals such as fluorite, chalcopyrite, marcasite, galena, pyrite, quartz, barite, and many other hydrothermal minerals.
Sphalerite occurs under a wide range of low- to high-temperature hydrothermal conditions in coal, limestone, and other sedimentary deposits.
References