New rocks for my aquarium

[AquaSerenity]

Hello all, I just wanted to share some of my latest hardscape pieces and ask for some advice.

Earlier today I managed to pick up 4 really nice looking rocks online via Kajiji.

Photos On Instagram

They were labeled as aquarium rocks and the guy who I got them from seemed very nice. Unfortunately I forgot to ask what type of rocks they actually were.

Can anyone identify these types of rocks? Is there anything I should be aware of before I put them into a tank?

 

[Autumnsky]

Natural Texas holey rock maybe.

 

[Kribensis_2004]

Fresh or salt water for the rocks, if it is salt water they likely will be okay but if it fresh I would check the parameters of your aquarium every two day to make sure they don't change that much, that being said I think they might be some kind of calcium based rock.

 

[Kribensis_2004]

are you sure they are not two types of rocks

 

[Autumnsky]

True, it looks like that latter pic could be a SW type coral "stone"