From the Verchniy Mine, on Rudnaya Mountain in the Dal'negorsk district. this is a gorgeous pair of parallel growth calcite crystals. Although calcite is common, the top quality calcite crystals from Dal'negorsk are famous for their lustre, sharpness and internal play of light. This specimen has all of those qualities - it is in excellent condition (no damage), sharp and glassy, and the top section of each crystal is water-clear, providing a wonderful internal play of light (and rainbow-type internal colour/sparkles).  The faces at these top terminations are as if faceted - they are stunning, and would have been worthy of inclusion in Goldschmidt. The calcite crystals are accompanied by small doubly-terminated black lustrous crystals of ilvaite. If you flip the piece over, the calcite crystals are in fact doubly-terminated but you'd need to display the piece with the "backside" facing forward to see that - and you wouldn't do that because the top terminations from the front view are so beautiful and are what make this piece special. 

The fifth photo shows the specimen illuminated by short wave ultraviolet light.