Kill it with fire or let it be (possible algae ID)

[GeetnBoas]

I'm very new to this hobby
matter of fact, i'm cycling my first tank as of yesterday with sand and live rocK I bought from my LFS.
what is this red and green on my live rock?
it was already present on the rock when I got it.
not finding any answers on previous fora.
please help.

 

[Ron Reefman]

If it's soft to the touch, it's probably algae and you don't want it. If it's hard to the touch, it's probably coraline algae which is good.