This well-flying species is prone to vagrancy and able to cross considerable distances of the open sea; it can thus be regularly found on the British Isles (though mainly in the south) and even on Iceland.

[2] The adult's wingspan is 18–21 mm (0.71–0.83 in); in their core range (e.g. Belgium and the Netherlands) they can be seen between April[citation needed] and November, but in outlying regions, they may only be regularly encountered in late summer and early autumn, when vagrant individuals abound.

This species is strongly sexually dimorphic: Males are light brown with a wavy pattern of whitish lines and a broad darker band running across the wings, forming concentric semicircles when the moth is at rest.

The females are slightly larger and much darker, almost uniformly blackish brown with an indistinct lighter pattern and a forewing spot like the males have.

Host plants recorded from the Central European part of its range include:[4] Euasterids I Euasterids II Eurosids II Basal core eudicots The widespread, strongly sexually dimorphic and somewhat phenotypically variable gem has been described anew time and again by various authors, even as late as the early 20th century, but all these supposedly distinct taxa are nowadays considered to refer to a single species.