[3] Slight differences between populations in the north and south of its range have led to speculation that it might have two subspecies.

Its slightly forked tail is iridescent bronzy gold and rosy gray on its upper side and glittering golden-orange on its underside.

It has a conspicuous white spot behind the eye and its gorget is glittering turquoise green.

[6] The black metaltail is found on the western slope of the Peruvian Andes from southern Cajamarca Department south almost to the Chilean border.

[6] The black metaltail's egg-laying season is thought to span from July to January.

One was on a steep mossy bank and the other two were built into the bases of unused nests of other bird species, perhaps a canastero of genus Asthenes.

Its presumed chase call is "a descending series of 4–6 high-pitched notes reminiscent of a Picumnus piculet".