At least 70% of this slab is a translucent crystal of hackmannite, the flourescent variety of sodalite. Under normal light, it is a creamy bluish-white. Under long wave ultra violet, it glows a bright orange-yellow, and gradually turns into a chery red (visible after the UV is turned off). Exposure to bright light (or a long time) returns the color to normal. The closeup is of the reddish hue.