The 10-year wedding anniversary is traditionally called the tin or aluminum anniversary. On the modern list, it is referred to as the diamond jewelry anniversary. Either way, it is the "first of the major milestone anniversaries," according to About.com.
The significance of the aluminum and tin to represent this anniversary is their flexibility, a major requirement in a lasting marriage. The significance of the diamond is its beauty and strength. Other symbols that go along with celebrating the 10th anniversary are the daffodil for its flower, the diamond or blue sapphire for its gemstone, and the colors silver or blue.