Description: Here the specimen has been rolled forward to expose the obverse (ie, backside) of the specimen. Note that the darker purple octahedrons have overgrown light blue cubic fluorite, occupying what would be the 111 face for the cubes. The olde-tyme thinking was that light-colored cubic crystals indicated a lower temperature of formation while the dark octahedral crystals formed at higher temperatures. So there would have to have been an increase in the temperature of the ore-forming fluid to produce what we have here. Fluid inclusion study is called for. But someone else is going to have to provide the rock for study. Mine stays intact....

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