BIXBYITE (Mn,Fe)2 O3
Crystal Description: Cubic
Bixbyite occurs as perfect, shiny, cubic crystals; often with
modified corners; may be 0.5 inches (12 mm) or more, mostly smaller.
Usually as single crystals, but may form penetration twins of two or
more crystals. At the Maynard Topaz Mine (Dana location) they occur
mostly as perfect cubes, showing no modifications. At the Solar Wind Mine the crystals are highly modified and can occur up to 1 inch on an edge.
Physical Properties:
Color- Black
Luster- Metallic
Hardness- 6 – 6.5
Specific Gravity- 4.5 – 5.5
Cleavage- Poor, actually quite brittle
Bixbyite, a rare mineral, was discovered in the late 1890’s by
Maynard Bixby, one of the early pioneers of the Thomas Range. Bixby
reported the location as being about 35 miles southwest of Simpson
Springs, in the southern end of the Dugway Mountains.
Arthur Montgomery and Ed Over rediscovered the location in
1934, however, it was actually located in the east central Thomas Range.
The discrepancy was due to the fact that during Maynard Bixby’s day
parts of the present day Thomas Range were considered part of the
Dugway Range. Bixby discovered several shiny black crystals perched
on cavity walls and also on crystals of topaz but had no idea as to their
identity. He sent several samples back east to his friend, A.E. Foote,
another collector and mineral dealer. Foote, unable to identify the min-
eral, enlisted Professor S. L. Penfield, at Yale University. Penfield found
them to be a totally new mineral species and, in 1897, he and Foote
named the mineral Bixbyite in Bixby’s honor. The site, now known as
the Maynard Topaz Mine (and also named in his honor), is now mined
commercially for topaz and bixbyite.
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Bixbyite usually occurs implanted on cavity walls, but may
also occur in combination with topaz, red beryl, or garnet. Bixbyite up
to 0.75 inches (18 mm) in size have been found in the northern Thomas
Range, however, in The Cove they seldom exceed 1/8” (3 mm) along a
cuboid edge. Bixbyite crystals are often modified by the tetragonal
trisoctahedron (211) and occasionally by the octahedron (111) or the
dodecahedron (011).