Can you help ID?

[jorge18]

Hi everyone, would you guys be able to help me ID what's growing on my rock here? Thanks!

https://www.flickr.com/gp/jorgetijerino/8poR80

 

[nereefpat]

Looks like a little cyanobacteria. If you can blow or brush it off, than it positively is.

 

[Dkuhlmann]

Actually it looks like the beginning of Coralline algae.

if you can't rub it off easily then it's Coralline. If you can rub it off easily then it's more than likely Cyanobacteria.

Diatoms are usually brownish color and mostly on your sand. They feed off of silicates in the sand.

 

[Highweigh]

I'd say cyano also