Mineralpedia Details for Sphalerite

Due to the mineral occasionally being mistaken for galena but generating no lead, Sphalerite was named for the Greek word sphaleros, meaning “treacherous.” This important zinc ore forms during low- to high-temperature hydrothermal settings as well as in coal, limestones, and some other sedimentary deposits. A highly common mineral, but a few localities produce fine crystals including Germany, colorless crystals from Switzerland, the Czech Republic, Romania, transparent crystals from Spain, England, Canada, the USA, Mexico, and Peru. Sphalerite is pyroelectric, generates a charge when heated. It can fluoresce under ultraviolet light, particularly specimens from Franklin, New Jersey in the USA which fluoresce orange and sometimes blue under long-wave ultraviolet light. It is also triboluminescent, meaning Sphalerite will generate light when broken.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/sphalerite.pdf

Formula

ZnS 

Crystal System

Isometric 

Crystal Habit

Euhedral Crystals, Granular, Colloform 

Cleavage

Perfect, Perfect, Perfect 

Luster

Resinous - Greasy 

Color

brown, yellow, red, green, black 

Streak

brownish white 

Class

Isometric - Hextetrahedral 

Fracture

Uneven 

Hardness

3.5-4 

WebMineral

View Sphalerite 

Mindat

View Sphalerite 

Absolutely perfectly formed modified tabular Sphalerite crystals with beveled edges in a cluster to 1.5cm set nicely on Limestone matrix with water clear Calcite rhombs.

One of the better Sphalerites we have seen from Lengenbach. A deep golden yellow-brown Sphalerite crystal to 7mm embedded in sugary white Quartzite matrix with minor Pyrite.

Although the Sphalerite crystal is partial, it's redeemed by the superb luster and color and because it has a tag from the 'Naturhistorisches Museum Bern' with a corresponding catalog number 9164 glued to the bottom of the specimen.

Jet black and very lustrous Sphalerite crystals to 7-8mm.

Gemmy yellow-green crystals of Sphalerite to 8mm.

Old piece with yllow-green Sphalerite crystals to 3mm.

Greenish yellow, gemmy Sphalerite crystals to 7mm on water clear Quartz in a large 5cm pocket with Pyrite/Galena matrix.

Large 1cm plus deep yellow to green Sphalerite crystals on Quartz.

This locality has been known for quite sometime amongst mineral collectors. The conventional wisdom was that these were Wurtzite crystals. According to Mindat, since 1962 these crystals were thought to be Wurtzite, until 1973 when Dunn said they were Sphalerite pseudos after wurtzite. Most recently, these crystals were shown by RRUFF to be polysynthetically twinned Sphalerite.

They are basically hexagonal stacked plates, much like Wurtzite crystals. Really, it's academic, but they are really nice micro crystals.

Excellent crystals of both green and yellow Sphalerite crystals to 3mm. Galena as well as Pyrite are also present.

Red Sphalerite crystals to 4mm with small 2-3mm frosted and cavernous Galena crystals.

Exceptional in form and size - Striated Sphalerite tetrahedrons to 2cm. I thought they were Tetrahedrite crystals at first glance, but a few of the crystals on the side are cleaved. 

Gemmy green Sphalerite crystals in excellent group of loaded with 4-6mm crystals.

Jet black and lustrous crystals of Sphalerite to 2cm across.