What is this strange holographic fluid dome.

[Rocketmagnet]

Yes, it does look a lot like a mood ring. The difference is that a mood ring changes colour with temperature, whereas this changes when you touch the back.

[sixtyten]

A bit like a mood ring

[Rocketmagnet]

Hi,
Many years ago, a friend of mine found this little trinket in a science museum gift shop (he thinks) but can't remember exactly where. I would love to buy another, but I can't for the life of me work out what it's called, or where I could buy one.

It's a clear plastic hemisphere. On the flat face is attached a sheet of black rubber, under which is a fluid full of holographic powder. If you touch your finger onto the flat side, you can see the fluid change colour (bottom left image).