This is one of the nicest sphalerite specimens I have ever had. Most twinned sphalerite crystals are multiple twins, and the shape is very complex. The dominant crystal on this piece is a simple twin of two crystals: one facing to the front and one to the back. The crystal form is well developed on both sides. The rectangular crystal faces are rough, perhaps etched, while the triangular faces are smoother. No damage. This piece was formerly in the collection of David London, after whom londonite is named. 5.8 x 8 x 4.5 cm. No damage.