Color change hackmanite is a very rare mineral from Afghanistan. Originally discovered in Canada in 1991. The Afghan material was discovered later. The Canadian material is said to fade in light, the Afghan material turns from a lavender to a amethyst in sunlight. This Afghan material fluoresces a bright peach under long wave uv light, and darkens the color from lavender to a purple. The more light it is exposed to the longer the color change seems to last when placed in a dark place to lighten the color again. After the color change to darken, when moved to a dark room, you will see it glowing a light blue. This material is not real common and tends to be very expencive when found.
This is very rare and very hard to find material. This specimen material is selling for $0.65 a carat and range in size from 1 carat up to 232+carats. The 232+carats specimen is with host matrix.