How do they get those lava/ river rocks used in hot stone massage to be so black?

[Max]

The one's I have turn into a light black when made wet or when oiled.
But I can't get them to have that shiny rich black luster that the massage stones shown in the "Hot Stone Massage Advertisements" have.

How can I get my stones to look like that?
I know it's best not to have anything done to the stones.
But if there is a way to make them look extra black, perhaps you could help me out.

I want the rocks to look perfectly black for display purposes and for taking photos of massages.

 

[LuvYaMimi]

The rocks are made of Basalt, which is a black lava (actual volcanic rock). It's not shoe-polish like the other person said. It's made by good ole Mother Nature.

If you want your stones to look a little darker in photos, add oil to the stones and snap pictures of them like that. They automatically get a little darker with water. Think of wetting cement, it looks darker.

 

[b r]

shoe polish