These are violet Nd laser garnets (Nd:YAG) cut in fantasy cuts. These are violet in normal light and turn pure colorless under fluorescent illumination. Each individual stone is labelled with its carat weight and letter in the photo and they can be purchased individually. Most of these stones have some bubbles--the large round has a prominent swirl of bubbles centered in it which is very cool.
This is Nd laser YAG, a type of lab created garnet used in lasers since 1964. It is still the most classic and widely-used variety. The color shifts from violet to pink to blueberry under different lights, and goes totally colorless under fluorescent illumination.
With a hardness of 8.5 it is ideal for use in all kinds of jewelry.
