International refiners make it convenient for investors to own bullion by offering silver bars in a variety of weights and sizes, ranging from one troy ounce to 400 troy ounces. Purchasing silver bars is a cost-efficient means of owning silver. Bars bearing the “hallmark” (logo) of the highly recognized refiners are the safest way to purchase. These refiners “assay” or test the metal for its purity or fineness. The bars are generally stamped .995 (99.5% pure silver) or higher purity, along with the individual bar’s weight. The top refiners are Johnson Matthey, Englehard, Credit Suisse, and the Royal Canadian Mint.