The Berylline Hummingbird, Amazilia beryllina, sometimes placed in the genus Saucerottia, is a medium-sized hummingbird. It is 8-10 cm long, and weighs 4-5 g.

Adults are colored predominantly metallic olive green with a rusty gray lower belly. The tail and primary wings are rufous in color and slightly forked. The underwing is also rufous. The bill of the male is straight and very slender. It is very dark red in coloration, almost black. The female is less colorful than the male.

The breeding habitat is in forests and thickets of western Mexico to central Honduras in Central America. It regularly strays to southeasternmost Arizona in the United States where it occasionally breeds (the Madrean sky islands). The female builds a nest in a protected location in a shrub or tree. Females lay two white eggs. This hummingbird is essentially non-migratory.

These birds feed on nectar from flowers and flowering trees using a long extendable tongue or catch insects on the wing.