This is not what you might expect in a Uruguay piece by quickly looking at it (an amethyst stalactite with solid quartz center). It is not a stalactite at all, in fact. It is hexagonal. The reason why...This is much more rare: it is hollow in the center - a crust that wrapped itself around a very sharply hexagonal crystal of calcite (if you look underneath, you can see this perfectly hexagonal hollow inside. The outside of this ectomorph, however, smoothed out the faces, so that is now appears perfectly rounded from the outside. The calcite was completely etched away by corrosive solutions in the pocket, leaving this amethyst "glove." Ex. Jaime Bird Collection.