Porcelaine anniversary

Today is my wife and I are celebrating our 18th wedding anniversary. From what I read online, it means we are celebrating our porcelaine anniversary. Although, according to Wikipedia, the 20th year of marriage is marked by the porcelaine anniversary and there's nothing between the 15th (crystal) and the 20th. So I am quite confused. Its gemstone is the chrysoberyl, commonly known as cat's eye. But in the end, what matters is that we will celebrate today with our little boy and that we built a family together.