"Twig" effect ring help

[Angeltruist]

I am seeing "twig-like" rings becoming regular and I have a great idea to use this look, but I can't seem to get the look right.

Could anyone give any advice on how they create the branch effect for a ring - is it a mould, or freehand? I am self taught in everything but can't seem to find any books or sites with this technique.
I've attached an image of a similar look I'm going for which I have found in a store.

thanks