This is one of my all time favourite stones to polish...:)
I chose these myself, they are very dirty/dusty when they come out of the ground.
Celestobarite is not a fan of the Sun! It make the surface of the rock dark brown like a old Teabag. Do not out on a windowsill and you will need to repolish your piece.
It is perfect for a corner of your room that you may want to add a splash of sunshine too.
Celestobarite can be found in the UK and some other parts of Europe.