I read somewhere that gold, silver are royal metals meant for kshatriyas and vaishyas and only copper, it's alloys are good to use for Brahmins, according to science Copper and it's alloys are antimcrobial, while silver exhibits germicidal effect only when it's wet or moist, so do Brahmins need to wear copper stuff on body to keep negative energies at bay, apart from doing Gayatri Mantra, wearing janivara, wearing rudraksha etc