People have been wearing jewelry for millennia. Gold and silver decorations are worn not only for aesthetic motives; in the past they were a symbol of power, wealth and even social status.
It is believed that jewelry made from precious metals have different effects on people, which is why it's unacceptable, and not just from an aesthetic point of view, to wear gold and silver at the same time. This is because these 2 metals cannot coexist peacefully with each other, or at least according to metal therapy.
Metal therapy is one of the relatively new advances in medicine. One of its founders was Norman Duke from the University of Michigan, who has discovered that when metal has contact with the skin there an electric shock forms.
When silver has contact with human skin, the energy is emitted from the skin to the metal, while with gold it's the exact opposite - the electric charge goes from the metal into the body. Their simultaneous contact with human skin sends conflicting impulses to the body and can lead to an energy imbalance in it.
This is also the reason why metal implants or metal tooth fillings shouldn't be used in the human body.
Wherever there's electrolytes, such as in saliva or blood, a galvanic reaction occurs, causing mini electrical charges, which is in turn linked to uncomfortable feelings and energy imbalance.