Left - Barite rose showing cluster of barite crystals that produce a rose-like appearance. Below – cleavage in barite (linear fractures within the crystals).
Barite crystallizes in the orthorhombic crystal system and may form aggregates or divergent groups of tabular crystals known as ‘barite roses’. These extraordinary crystal aggregates have a very pleasing appearance and often are sought by mineral collectors.
Barite has perfect basal cleavage with prismatic cleavage at right angles to basal cleavage, and will sometimes form white masses exhibiting distinct right angle prismatic cleavage. Tabular white, yellow, grey, blue, red, or brown, opaque, translucent and transparent crystals have been reported.
Some Wyoming Localities
New Rambler mine (SW section 33, T15N, R79W). Fine-grained to massive pyrite was reported with barite crystals at the New Rambler copper-gold-palladium-platinum mine in the Medicine Bow Mountains west of the Rob Roy Reservoir.
Shirley Basin. White barite concretions are reported in Shirley Basin northeast of the town of Medicine Bow. These are weakly fluorescent under long-wavelength ultraviolet light.
In addition to white barite, very attractive aquamarine blue barite crystals occur in the vicinity of Sheep Creek near Crystal Hill adjacent to the Mine Hills (section 10, T26N, R75W) along the southeastern margin of the basin and adjacent to the western flank of the Laramie Range. Mine Hills are located on the Laramie Peak 1:100,000 topographic map and are accessed from the west from Shirley Basin (see also Shirley Basin 1:100,000).
The barite occurs as attractive light-blue, transparent to translucent, tabular crystals and is found with calcite and quartz in vugs in the Casper Formation near a massive psilomelane, manganite (manganese) and jasper replacements in the Casper Formation (Hausel and Sutherland, 2000).
Blue barite crystals from Shirley Basin.
Dana, E.S., and Ford, W.E., 1949, A textbook of Mineralogy: John Wiley & Sons, 851 p.
Hausel, W.D., and Sutherland, W.M., 2000, Gemstones and other unique minerals and rocks of Wyoming: Wyoming Geological Survey Bulletin, 267 p.
Sinkankas, J., 1964, Mineralogy: Van Nostrand Company, 585 p.
Other Blue Barite specimens from the Mine Hills, Shirley Basin, Wyoming.