I checked in my Reef Coral book by Paul Humann. Closest thing I see is the Red algae. From the book; "There are a number of species in several genera that generally form thin, brittle, highly calcified encrustations and rounded plates. Occasionally their outer edges extend outward from substrate. They are usually dark red to burgandy, violet, lavender or pink, often with thin white margins. May be quite fragile, especially along extended edges. Colonies are so individually variable in appearance, and yet similar to one another, that they cannot easily be distinguished visually. Positive indentification requires laboratory examination." HTH