Perhaps the most significant gift from her husband, Kate's wedding band is made of Welsh gold that belongs to the royal family. As in, the royal family casually has a stockpile of gold. Shrug! Per a royal spokesman : "The wedding ring that Catherine Middleton will wear will be made of Welsh gold. The gold was given to Prince William by The Queen shortly after the couple were engaged. It has been in the family's possession for some years and has been in the care of the royal jewelers. There are no further details on which mine the gold was mined from." Mine receipts or it didn't happen, tbh.