Ferrimolybdite (?) [Fe.sub.2](Mo[O.sub.4])[.sub.3] * 8[H.sub.2]O (SO)
Ferrimolybdite or a closely related mineral occurred on the north side of Battle Mountain as bright yellow, capillary crystals in cracks and joints of weathered plagioclase phonolite, and with ilsemannite as an alteration product of molybdenite in a vein exposed in the Ophelia tunnel (Lindgren and Ransome, 1906; Eckel, 1997).
A specimen from the Roosevelt Drive area south of Butte exhibits ferrimolybdite as bunches of canary yellow prisms in cavities in deeply altered and iron oxide-stained quartz monzonite (JL).
Ed was fairly free with information on where he self-collected and, as a matter of interest, I've listed a number of these: at the Crown Point mine, Lake Chelan, Washington (large molybdenite crystals in quartz); the Blackbird mine, Cobalt, Lemhi Co., Idaho (vivianite-ludlamite); the Beaver mine, Beaver Mountain, British Columbia (linarite); the Rock Candy mine, Kennedy Creek, British Columbia (fluorite-barite in large crystals and specimens); Majuba Hill, Pershing Co., Nevada (clinoclase-olivenite); [near Lost Trail Pass] Lemhi Co., Idaho (ferrimolybdite
There were brilliant blue balls of carbonate apatite from Humboldt County, Nevada, gorgeous realgar clusters from the Getchell mine, wavellite from the Willard mine, ferrimolybdite
from Idaho, erionite from Tunnel Beach, Oregon, and so on.
Ferrimolybdite [Fe.sub.2][(Mo[O.sub.4]).sub.3] [multiplied by] 8[H.sub.2]O
Pale yellow coatings of ferrimolybdite occur with traces of visible molybdenite in quartz in a few places in the mine, especially the Watercourse Raise.
Szenicsite joins ferrimolybdite
, lindgrenite, powellite and wulfenite as a simple molybdate.
Molybdenite and ferrimolybdite
are also known from the Wise mine, and it is believed the wulfenite probably formed as a result of oxidation by downward migrating groundwater.