Gold vermeil (pronounced ver-may) or electroplating is heavy gold plating (2.5 microns by US standards) over 925 Sterling Silver. It is hypoallergenic, so people with metal allergies can wear it safely. Since the gold plating in vermeil is much heavier than gold plated jewelry, the gold lasts much longer and will not rub off (although over time, some gold may wear off if not taken care properly and exposed to water, sweat or perfume often times).
Please see HERE how to take good care of your electroplated jewelry.