Do you like black? If yes, then you will love the Black Obsidian Wand. It is really black with no obvious rainbows or other colours in it. As the wands look identical I will intuit the right one for you.
It has two differently sized round ends so two different deeps can be done to massage out knots. But a whole heap of people buy it just to hold as its so pretty. And you can read more about the how to use a crystal wand.
Most people will buy this crystal wand as a powerful shield against negativity especially of mental type but do not overlook its help in understanding life experiences so you stop being negative. Also as a shield when massaging.
Black obsidian was a crystal recommended by Chinese Traditional Medicine Masters.