The 15th anniversary is referred to as the crystal anniversary. The traditional gift for this anniversary is a watch or piece of crystal for both the husband and wife.
The 15th anniversary is a milestone in any marriage. The gemstone that symbolizes this anniversary is the ruby and the official flower is the rose. The 20th anniversary is known as the china anniversary with the traditional gift being something made from china, although modern gift givers now gift platinum for the 20th anniversary. The 25th anniversary is the silver anniversary and the traditional gift given to the couple should be made of silver.