The Shining Sunbeam is a large, dark-brown hummingbird with a lilac-gold iridescent lower back and rump. Like other sunbeams, it has a proportionally short bill for a hummingbird. Found at high altitudes, the Shining Sunbeam inhabits semi-arid montane ridges and cloud forests. Most populations are altitudinal migrants, descending seasonally to lower elevations. The Shining Sunbeam forages mainly on nectar, but will also eat arthropods; males have been known to aggressively defend feeding territories from other hummingbirds. There are currently two described subspecies of the Shining Sunbeam. Neither sex has any white in the plumage, which helps distinguish the Shining Sunbeam from other species in the genus Algaeactis.