Meet CiM Jellyfish - a colour shift glass like the colour in commercial beads known as "Alexandrite" - and like the Effetre 081 Dark Lavender.
This colour of glass looks blue in cool, fluorescent light, and mauve in warm light, like incandescent or sunlight.
This series of photos show the rather remarkable range of colours you will get as you move from one kind of lighting to another.
Pictured to the right, two self coloured beads and Jellyfish encased over white.
It can be something of a challenge to create with this glass, as you have to coordinate your colours for all types of lighting.
That said - I find it a really nice glass to work. Try it over silver foil sometime.
It's a neat piece of chemistry.