Brandburg quartz - a beautiful example of an amethyst skeletal crystal, with very visible and deep etchings and layers. The crystal has a good clarity with layers of deep smoky quartz and a fine amethyst centre; and the termination is nice and clean: this resembles a star when looked at from above, and so is a very unusual example.
Size 6.7 x 3.3 x 3.3 cm