Dims: 6.87x3.74x0.46" (17.44x9.51x1.17cm)
Wt: 13.33oz (378g)
This large slab consists of at least 40% hackmannite, the fluorescent variety of sodalite. I believe that the blue mineral is more sodalite, and there are veins and spots of other minerals, probably including calcite. While the blue sodalite areas are opaque, the hackmannite is white and translucent. When exposed to UV light, it glows a very bright yellow (much better than the images imply), and gradually changes (normal light) color from white to pink to red. Exposure to bright light (such as sunlight) erases the pink, leaving the original white hackmannite. The slab has been cut and polished, smooth on one side but a high gloss on the other. The gloss is so good that I suspect it may be a layer of a shellac or similar material, although I can find no indications of overlap or missing coverage to confirm that, and it may indeed be a high polish.