Is this natural rock?

[Jcm707]

Hey so I bought this from a seller when I first set up my tank and didn't use it because it's black and I thought live/dry rock was supposed to be white. Anybody know what it is?

 

[Dragonvale]

Is it dense? Maybe a base rocks since those are generally denser. I had base rock that were darker but more of a creamier brown.

 

[Jcm707]

Is it dense? Maybe a base rocks since those are generally denser. I had base rock that were darker but more of a creamier brown.

Yeah it's dense. It reminded me of like that lava rock stuff used in freshwater but yeah it it's also somewhat brown. I guess it came out of a a 300 gallon reef so it was probably base rock then.