The Violet-chested Hummingbird occurs in humid mountain forest in northern Venezuela. Records in Colombia are localized around Tamá, and males have a conspicuous violet-blue chest patch.
The male has a parrot-green crown and throat, an ultramarine breast and chest, and a black belly. The outer two, sometimes three, olive-green tail feathers have white tips. The female has white underparts with iridescent green disks centered on the feathers and a cinnamon abdomen. The bill is elongated and somewhat bulky, with a slight downward bend.
Among 67 nests studied in Yacambú National Park, Venezuela, females alone built nests, incubated, and fed the young. Clutches usually held two eggs; incubation averaged about 20 days and the nestling period about 26 days.
An extinction-risk assessment has not been added yet.