The lichen's thallus is typically light olive-green to yellowish, often covered in orange pigment, and varies in texture from smooth to uneven.

[5] André Aptroot and Robert Lücking transferred it to the genus Astrothelium in 2016 following a large-scale reorganisation of the Trypetheliaceae based on molecular phylogenetics.

[6] Astrothelium aeneum has a corticate (having a cortex-like structure) thallus, which typically appears as a light olive-green to yellowish colouration.

These ascomata are generally found either solitarily, irregularly merging with each other, or spreading diffusely in a pseudostromatic pattern.

Its presence has been recorded in various countries including the United States, Costa Rica, El Salvador, the Revillagigedo Islands, the Bahamas, Cuba, Jamaica, Colombia, Venezuela, Guyana, Suriname, French Guiana, the Galápagos Islands, Bolivia, Brazil, Sri Lanka, Thailand, and Malaysia (specifically in Sarawak and Sabah).