hackmanite
Hackmanite is a variety of sodalite.
It is also known for its unique property of changing color when exposed to ultraviolet light and not returning to its original color for a while.
Colorless, white, gray, blue, purple, red-purple and other shades are found.
Karatz GemMagazine
" Hackmanite "
Karatz GemMagazine
" Hackmanite "