Q: I’ve never seen blue mold before. Have you?
A: I think it’s cobalt crust, Terana caerulea.
It is a type of white rot fungus, because it can break down all components of the plant cell wall, including brown lignins, thus leaving the white cellulose exposed. It is usually found on the underside of logs, near the soil, which explains why it is uncommon to see.
If we didn’t have these and other fungi, we’d be covered up with tree branches and other woody materials!