does it have viens like a leaf would? It looks really odd in the pic.... almost like a large paint chip or something smooth like that. maybe a higher resolution pic would help a little more. I hope somebody else has a better sense of what this is so they can help you out.
Tough to tell from your picture really.. I guess it could be Red Blade
I cannot get the link to work for some reason, but LAreefs.com has some for sale on the 3rd page of their macro algae section.. Feel free to check it out.. Wish I could get the link to work..