These earrings are made by the artisan of Jaipur in India. They are made of brass (an alloy of copper and zinc)and silver plated.
 
Brass is a good alternative to gold, it does not change color or break down over time.It does not cause allergies, so you can wear it without fear.

It is also very easy to clean by rubbing it with a little toothpaste or soap and lemon juice.
Signification
Snake: regeneration, immortality, fertility.