[2] Chiodecton montanum is distinguished by its yellow pigments (secalonic acid derivatives and skyrin) in the medulla, a thallus that is tightly attached to the substrate, and a hymenium infused with oil droplets and granules.

Chiodecton montanum has a thallus (lichen body) that can be either smooth and very thin or slightly roughened (verruculose), with a thickness of 0.5–1 mm.

When tested with potassium hydroxide solution (K+), parts of the thallus react by turning yellow or reddish-yellow, indicating the presence of secalonic acid pigments.

The thallus is typically bordered by a black prothallus, a thin layer of fungal growth that helps define the lichen's boundary, and can form large, continuous patches that cover areas of up to 50–100 cm across.

Each stroma is constricted at the base and roughly globose (rounded), often covered with a whitish powdery coating (pruinose).