Hard growth

[chester]

I noticed this growing at the base of my gorgonia a while back and assumed it was soft algae but the the other day I touched it by accident and found it to be a very hard growth of what I pressume is some form of alge, any ideas what kind and how big it may grow?picture can be viewed on site below.
THANKS!

http://community.webshots.com/user/ventnor100

 

[Manofathousandpolyps]

Looks to me like a red form of halimeda. Ive only seen one other picture of this form so Im not totally sure.