Quote Originally Posted by khaos View Post
I buy this explanation too. I still am in the camp that there may be some oil or soap in the mix somehow too though, because I simply can't think of a mineral that would make an elastic slurry, or even something that would increase the surface tension of water (let me remind you most things decrease surface tension...)
Well, who knows what was going on when this stone was forming. There could be trace amounts of organic material that, with water added, mimics the characteristics of soap. I think some salts have detergent properties as well. As for the surface tension, soap decreases surface tension. I think bubbles will form more easily when the water's surface tension is decreased. Of course, without a detailed analysis of this particular stone, we can speculate until the cows come home and never have a definitive answer.

It would be nice to know what is causing the bubbles and if that is what gives this stone it's outstanding polishing properties. If it is some salt or organic material, perhaps we could sprinkle it on other coticules (like fairy dust) to enhance the stones performance as a hone.