The smooth crystal faces on this specimen are aligned perfectly parallel to each other, so light bounces off in a brilliant, flashing, mirror-like display.  This kind of quartz is called jacare, from the Portuguese word for alligator.  In fact, the parallel faces, which are higher than the surrounding quartz, do look like the back of a submerged alligator!  The specimen is a very pale smoky color with dark edges, and the crystals are sharply formed.