In a nutshell, vermeil (French for silver, 5月と発音) refers to a variety of gold-coated metal. For metal to be considered vermeil, it needs to meet three main trade criteria:
The base of the metal must be of sterling (92.5%) or fine (99.9%) 銀. This is why vermeil is also known by its other names: Silver Gilt or Gilded Silver
The purity of the gold must be of at least 10 karats
The thickness of the gold coat should consist of a minimum of 2.5 ミクロン (0.0025 millimeters)
If these three criteria are not met, then the metal becomes gold-filled or gold-plated (more on this later). You can also find gold vermeil in other colors such as rose gold, Hamilton gold and so on. The color you choose depends on your preferences.
While gold vermeil is popularly used in jewelry, it is a versatile metal and has its other uses as well. A good example is the Vermeil Room of The White House. This famous room contains a wine cooler and tableware all made of vermeil. You will find vermeil being used in fixtures and furniture among other things. Also, many sports trophies and all Olympic gold medals are all made of gold vermeil.
Gold vermeil was a popular Victorian Era feature and was used heavily in jewelry, tableware and other items.