I recently purchased this stone from a fellow ebay seller. It measures approx. 10"x5"x5", is cut, and has a custom dai. I really like it, but don't know much about it as I am very new to suiseki. I know it was collected in California, but thats about it. What kind of stone is it? There also seems to be some sort of wax-like substance coating the stone, and I'm not sure if I should clean it all off, or leave it. Any suggestions?