This is just a wonderful, aesthetic combo specimen from Naica, among the most unique I can recall seeing. The matrix is a lustrous and translucent, doubly terminated, milky white rhomdohedral crystal of calcite measuring 5 cm across. Perched aesthetically on the calcite crystal are 3 complexly intergrown octahedrons of lustrous and translucent, lavender-purpley fluorite to 2.6 cm in length. As if their intergrowth were not complex enough, they exhibit stepped growth which creates a myriad of reflecting facets. For added measure the fluorite crystals are studded with brassy yellow pyrite crystals, to 2 mm across. Superb in every way, this is a unique specimen far beyond the usual combo. You couldn't make better aesthetics if you glued it together. Comes with custom lucite base already made for the specimen. This specimen was on loaned exhibit in the University of Arizona Museum for over a decade until my purchase of this collection in 2008.