Dims: 0.30x0.29x0.23" (0.77x0.74x0.58cm)
Wt: 2.5ct (0.5g)
Mesquitic, San Luis, Potosi, Mexico
This is an excellent example of the rare tourmaline, buergerite. It has the typical luster and form of tourmalines, and to my eye the brown color is different than that of dravite. The crystal is nearly opaque - the only hints of translucency comes from the surface texture, which does look translucent to transparent at a barely perceptible level under a 15x loupe. The specimen is nearly doubly terminated and undamaged, except for a missing section near the top where a cavity exposes what I think is the remainder of another buergerite crystal that broke away. There are also a number of prismatic cavities which once held quartz crystals - a few of which remain on the specimen. The back side of the crystal is incomplete, and a loupe shows that it consists of several partial crystals and is likely the attachment point to the original substrate.