This is a piece of bright blue green Tourmaline rough that will cut a nice stone. it has an open C axis meaning it will cut a very nice and bright gem.
There are some inclusions in the middle of the stone that might cause some issues. It might need to be cut in half to get the best yield. A challenging stone but the results will be worth it.
The tourmaline is a unique miracle of colour. The gemstone comes in green, red, blue, yellow, but there are also colourless specimens and black ones. Often two or more colours are found in a single tourmaline crystal. Also rare and very highly esteemed are tourmalines which appear to change their colour and cat’s eye tourmalines. Having said all that, green is regarded as the classical tourmaline colour.