Both sexes of all subspecies have a straight black bill, a white stripe behind the eye above a dark cheek, and a slightly forked tail.

[5] Adult males of the nominate subspecies have green upperparts with a bronzy rump and bluish black uppertail coverts.

[5] The subspecies of green-throated mountaingem are found thus:[3][5] The species inhabits the interior and edges of humid evergreen and pine-oak forest.

What is thought to be the green-throated mountaingem's song is "a complex warble of squeaky notes and buzzy, gurgling trills, 'tsee-tsee-glr-tsee-glr-tsee-glugluglugluglu-glr-glr-tsee'."

"[5] The IUCN has assessed the green-throated mountaingem as being of Least Concern, though its population size is unknown and believed to be decreasing.