What does "topaz" mean?

Topaz: (Zoöl.) Either one of two species of large, brilliantly colored humming birds of the Topaza, of South America and the West Indies. Note: The two tail feathers next to the central ones are much longer that the rest, curved, and crossed. The Throat is metallic yellowish- green, with a tint like topaz in the center, the belly is bright crimson, the back bright red. Called also topaz hummer. False topaz. (Min.) See the Note under Quartz.