Thallus rimose to areolate, up to 5 cm diam.; hypothallus usually distinct, black; areolae up to 0.5 mm diam., greyish white to medium grey, dull, contiguous or scattered, more or less angular, plane; medulla KI–. – Apothecia up to 1 mm diam., black, epruinose, orbicular, remaining more or less plane or becoming moderately convex, narrowly marginate; excipulum brownish black in the rim, inner part paler brown, K–; hypothecium brown, K–; hymenium colourless; epihymenium bright green to greenish black, K–; paraphyses with a sharply delimited, green pigment cap in the apical cell; no crystals or granules in the apothecia; ascospores 8 per ascus, 1-septate, persistently colourless, 14–17 × 6-9 µm. – Conidiomata not seen.
No lichen substances.
On crystalline schist.
The species is rarely collected. It is morphologically similar to R. caeruleoalbum and differs mainly in the absence of stictic acid.