Click on the picture to see a magnified view of the beads

I haven’t been able to find out much about this stone. It appears to be referred to as Tree Agate in some cases, but I’m not too sure.
If anyone can shed any light on the origin or properties of this stone, I would love
to hear from you. Many thanks. Suggestions received so far as -
Description
Creamy pale stone with strong, dark, forest green markings and patches. Sold as temporary strung 40cm (approx) strands.