Bryce Colwell Collection The Black Pine Mine in Philipsburg is certainly best known for its world-class veszelyite crystals, but much more was produced from the mine. Fine quartz twins and tetrahedrite crystals like this one are just two examples. This is an exceptional dome of sharp black tetrahedrite crystals with clear quartz in association. Stolzite crystals rarely show up with the tetrahedrite, but none are to be seen on this one.