It has a medium-length straight black bill, dark cheeks, and a white stripe behind the eye.

Their central tail feathers are dark metallic to bronze green and the outer ones paler.

Their throat and belly are dark rufous and the undertail coverts are gray with white or buff edges.

The white-throated mountaingem makes high pitched calls described as "ziit or ziip" and also "a 'sputtery, bubbly' song".

[8] The IUCN has assessed the white-throated mountaingem as being of Least Concern, though it has a small range and its population size and trend are unknown.