I think its some sort of sps
It is not soft but hard like a rock with no real attachment. Looks like they are part of the rock. Or I cannot see where attached.
It was turning white till I put the lights on and now seems to be coming back darker green
Did it come on live rock from the Caribbean? If so, it is an lps coral called rose coral. I have one from my live rock. Really pretty in the full spectrum lights. Mine is red and green. In not so full, more brown and greenish.
First pick when rock in qt. Next is from Sept. Now it is full, bright and growing.