Astonishing hummingbird of intense purple feathers in frontlet, breast and underparts that glows and shines in proper light but that otherwise looks intense black. Present only in Colombia and western Ecuador, between 350-2200m.

As other members of the Boissonneaua genus, it lifts its wings momentarily upon landing. It is rather uncommon but can be seen reliably at the feeders in Las Tangaras Reserve.