Wikipedia
Silver-gilt or gilded/gilt silver, sometimes known in American English by the French term vermeil, is silver gilded with gold. Most large objects made in goldsmithing that appear to be gold are actually silver-gilt; for example most sporting trophies, medals (such as " gold medals" in all Olympic Games after 1912), and many crown jewels. Apart from being much cheaper than gold, large silver-gilt objects are also much lighter if required to be lifted, and stronger. Compared to plain silver, for delicate objects like the Nef (illustrated), or those with much intricate detail like monstrances, gilding greatly reduced the need for cleaning and polishing, and so reduced the risk of damage to them. The "gold" threads used in embroidered goldwork are normally also silver-gilt.