Location:

Henderson Mine, Colorado, USA

This belongs to the Climax-type class of porphyry molybdenite deposits. The Henderson orebody is associated with the Henderson granite and Primos and Urad porphyries. A central potassic zone carries a major silicified zone and the orebody is coincident with both of these. Quartz-topaz, phyllic, argillic and propylitic zones lie at progressive distances from the central potassic zone.

Major Minerals:

Molybdenite, pyrite, magnetite

Minor Minerals:

Haematite, sphalerite, galena, hubnerite

Trace Minerals:

Include ilmenorutile, columbite, uraninite, uranothorite, brannerite, xenotime, monazite, zircon (within the associated igneous rocks)

Textures:

Molybdenite occurs in thin quartz veins where it lies along the vein walls or within the vein as discrete laths, polycrystalline clots or rosette-shaped aggregates. Magnetite associated with minor haematite occurs in quartz veins and is rimmed and cross-cut by pyrite. Hubnerite occurs with pyrite and topaz in quartz veinlets. Pods of molybdenite, magnetite, pyrite, topaz and muscovite are present

Reference:

Wallace et al., 1978