Green stuff but NOT algae

[sen5241b]

This green stuff is on my live rock. I put the live rock in three weeks ago and I could swear it wasn't there at first. It is hard to the touch --like rock. I even scrubbed it a little with a brush and it didn't come off. What is this stuff?

http://mindofscott.com/Images89v498098/GreenHardStuff0002_800x600.jpg


http://mindofscott.com/Images89v498098/GreenHardStuff0003_800x600.jpg

[cocoa_pleco]

i thinks its maybe the start of coraline algae, though really coraline is purple

[sen5241b]

The guy at the Fish store said the same thing. No known coralline algae has ever been this color.