What is Vermeil?
From Wikipedia: Vermeil, pronounced vərˈmeɪ is a combination of sterling silver, gold, and other precious metals, commonly used as a component in jewelry. A typical example is sterling silver coated with 14 carat (58%) gold. To be considered vermeil in the US, the gold must be at least 10 carat (42%) and have thickness equivalent to at least 2.5 micrometres of fine gold (a 12 carat [50%] plating would need to be 5 μm thick). In the US, sterling silver covered with a base metal (such as nickel) and plated with gold cannot be sold as vermeil without disclosing that it contains base metal.
The US Code of Federal Regulations 16, Part 23.5[2] defines Vermeil: "An industry product may be described or marked as 'vermeil' if it consists of a base of sterling silver coated or plated on all significant surfaces with gold or gold alloy of not less than 10 karat fineness, that is of substantial thickness and a minimum thickness throughout equivalent to two and one half (2½) microns (or approximately 1/10000th of an inch) of fine gold."
