[3][4] The crimson topaz was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae under the binomial name Trochilus pella.

[5] Linnaeus based his description on the "Long-tail'd red huming-bird" that had been described and illustrated by the English naturalist George Edwards in 1743 from a specimen owned by Charles Lennox, the Duke of Richmond.

[10] The subspecies of crimson topaz are distributed thus:[3][10] The species mainly inhabits inland rainforest in lowlands and foothills at elevations up to 500 m (1,600 ft).

[10] The crimson topaz is mostly sedentary during the breeding season but at other times appears to roam elsewhere seeking flowering plants.

The female builds a cup nest of Ceiba seed fibers and spider web, often on vertical branches or in vines, and often over water.

The crimson topaz's song is an "irregular series of chattering 'chip' notes given almost continually (other than breaks to feed) throughout the day."

[10] The IUCN has assessed the crimson topaz as being of Least Concern, though its population has not been enumerated and is believed to be decreasing.