Whats the name of this rock/stone?

[tommy_zito]

i have some in my 10G and it seems to be fine..

 

[Mavrick813]

thanks so much for the info! So its beneficial as well as looks neat! I plan on using some pieces in a tank with black sand.

The White Holey Rock on Black sand would look good IMHO. But expect some Algae growth on the Holey Rock. It could be I'm doing something wrong, But no matter what I get a light Green Algae on mine. I take the rock out every so often and give it a scrub down with a tooth brush and some tank water. But not as often as I'd like/should.

G/L with it.