What’s a good stone or type to look into is there a Color preference in lhp work or would any type work?
It’s not the colour you should prefer but the properties that each stone can offer you, based on your work.
It is a personal choice really. No real set standards to follow, unless you are following a specific tradition that would have them.
I have one made of black obsidian, which has a personal meaning due to events in my childhood.