Śatapatha Brāhmaṇa ("of a hundred paths") 6.7.1.4

6.7.1.4

yadveva rukbham pratimucya bibharti | reto vā idaṃ siktamayamagnistejo vīryaṃ rukbho 'smiṃstadretasi tejo vīryaṃ dadhāti

And, again, why he puts on and wears the gold plate;--this fire is seed poured out here; and the gold plate means vital energy (or brilliance) and vigour: he thus lays vital energy and vigour into that seed.