A single, well-formed crystal of Dioptase, measuring an impressive 20 mm in length, attached to a small fragment of Calcite matrix and with a smaller, 7 mm Dioptase crystal protruding from the side. The colour and lustre of the main Dioptase crystal are excellent - a deep emerald green with glassy surfaces and bright internal reflections - and there are only the very slightest of abrasions to one of the upper crystal edges, but really magnification is required to see this. The crystal shows the classic form for Dioptase - a hexagonal prism, terminated by rhombic faces. Two sides of the lowest quarter of the crystal are damaged from where it was formerly attached to another crystal, meaning the the lower termination is incomplete, but overall this is a very fine displayable large single crystal of this colourful and attractive rare copper mineral. The crystal is mounted on a small acrylic base for display.