Donald Morelli, a professor of chemical engineering and materials science at Michigan State University, led the team which developed the material based on natural minerals known as tetrahedrites.
The mineral family that they mimic is one of the most abundant minerals of this type on Earth - tetrahedrites.
I didn't even know Butte had world-class rhodochrosites, tetrahedrites
and chalcopy-rites, and 3-inch covellite crystals
In 2001, very nice, lustrous tennantite (X-ray verified) was found growing on pyrite; unlike the similar, and more common, tetrahedrites from Casapalca, these crystals are simple tetrahedrons to about 3 cm.
Some of the tetrahedrites have been naturally corroded, and are irregularly pitted, the holes overgrown by very small calcite scalenohedrons.
Luzonite forms tetragonal bipyramidal crystals to 1 cm covered by small tetrahedrite crystals; it has also been identified as tabular reddish violet metallic crystals to 4 cm with cores of enargite.
A new vug produces some beautiful chalcopyrite-coated tetrahedrites that look like old Cornwall specimens, and about 90 rhodochrosites, including a 1 1/2 x 1 1/2 x 1 1/2-inch rhomb on quartz and a 1 1/2 x 1 1/2 x 1 1/2-inch killer.
July 25: In the Tetrahedrite Drift, the best tetrahedrites yet found: big plates with 1 1/2-inch lustrous crystals, come from the Museum Pocket.
There are bright tetrahedrites to 3/8-inch and bright druses of chalcopyrite and sphalerite, but no fluorite.
The tetrahedrites occur in crystals to over 8 cm in size; they are some of Peru's largest and, it can be argued, some of Peru's best.
The dominant mineral assemblage at the margins of the district is sphalerite, galena, calcite and Ag-bearing tetrahedrite.
Except for the radically different morphology, these suggest the old chalcopyrite-coated tetrahedrites