Gold and platinum have long symbolized the precious nature of marriage. Both are noble metals that in their pure form do not corrode or oxidize. For jewelry the metals are mixed with base metals to produce a harder wearing and strong metal; as the pure form is generally too soft for everyday wear. Wedding rings are generally 14k (58.5% gold) or 18k (75% gold) or long term durability. Platinum is alloyed typically to 95% purity. Learn more about metal types here.