Is this rock safe to put in my tank?

HI everyone!
I've had this rock in my house for about 4-5 years. I got it from a guy that gave up on fishkeeping, but I never put it in my tank because my 10 gallon was just too small for it.
Anyways, the rock is really cool, it has lots of minI caves but will it tear my fish's fins and body? That's the problem.
Thanks for any heads up.

 

Looks to be a quartz aggregate.
Chemically, it should be ok.
What fish are you worried about with their fins?

 

Looks to be a quartz aggregate.
Chemically, it should be ok.
What fish are you worried about with their fins?

Really? I thought it might be limestone. How did you tell it's quartz aggregate?
Well, I might change my stock in the late future, so GBR, honey gouramis, neon tetras (other tetras as well perhaps), harlequin rasboras, cory cats, ottos... mostly these. A long list, I know. What do you think?

 

ehhhh looks a bit rough for my preffrence.

 

Really? I thought it might be limestone. How did you tell it's quartz aggregate?

40 years of collecting rocks and 11 years of selling them.

Limestone generally wears more smoothly than the rock you show.
I freelly admit I may be mistaken, a closer/tighter shot would help.