Atharvaveda 12.3.54

12.3.54

tanvàṃ svargó bahudhā́ ví cakre yáthā vidá ātmánn anyávarṇām |
ápājait kr̥ṣṇā́ṃ rúśatīṃ punānó yā́ lóhinī tā́ṃ te agnáu juhomi ||54||

The heaven-goer hath variously changed his body, as he finds (? vidé) in himself one of another color; he hath conquered off the black one, purifying a shining one (rúçat); the one that is red, that I offer (hu) to thee in the fire.