Hey DoubleTerm... If you are offering a chance to collect some rhodo (possibly flourite and apatite as well) I'd love the opportunity... I've always had a fascination with it... I've done some research and found this:
Geologic section and gravity profile across the Climax and Alma districts:
The Sweet Home mineralization is posed to be related to magmatic activity that formed the inner Alma dome at about 24 - 28 million years ago (Bookstrom et al. 1988; Bookstrom 1989). We assume that a hidden molybdenum porphyry deposit in a satellite intrusion of the Alma Batholith is below the Sweet Home
system, similar to the currently exposed Climax molybdenum deposit.
Two distinct mineralization stages are present in the mine; an early assemblage containing quartz-molybdenite-pyrite-topaz-muscovite-fluorite, and a later assemblage containing galena-sphalerite-tetrahedrite-bornite and other sulfides/sulfosalts, and fluorite-rhodochrosite. Calcite, barite, and apatite were the last minerals to form. Tungsten mineralization, in the form of hübnerite, and early black sphalerite are common. It is not clear whether these minerals are associated with the early mineralization stage or are transitional between the two main stages. Secondary copper minerals locally replace tetrahedrite.
The article also says the gem quality rhond comes from magmatic hydrothermal alteration and the lighter colored "washed out" rhond was formed by diluted by minor amounts of meteoric ("groundwater") water towards the end of the mineralization.
I've added a couple of images from the article: a geological interpretation of the subsurface and a mine map for anyone who's interested.
The web URL for the article:
http://edoc.gfz-potsdam.de/gfz/get/12489/0...b9f0a/12489.pdf