What is this on my dry rock?

[MysterioMask]

I was cleaning newly acquired dry rock and found his clearish substance on a hole. It is hard and solid. Should I try and remove it? Any idea what it might be?

 

[Jisko]

looks like an old dried sponge

 

[Ty Hamatake]

If it's hard and on dry rock I don't think it would be a sponge. Looking at the rock, it seems to be some type on mineral deposit. What kind? I have no idea, but I don't think it's organic.

 

[Monkeynaut]

It won't help you identify what the thing is in the rock... but it will help you get the rock into a safe condition for your tank.
https://www.reef2reef.com/threads/d...than-natural-cures-brstv-investigates.306360/
Good Luck!