Occurring in nature in metallic form, these two precious metals can be produced sans the use of extraction metallurgy. These other characteristics of gold and silver make them both well suited for coinage: They are not radioactive. They are more ductile or softer than most other elements. They are less reactive compared with other elements. The Manx Noble: The Manx Noble platinum bullion coins were minted from 1983 to 1989 by the Pobjoy Mint, the leading private mint in Europe. The coins were offered in five varieties: 1. 1/20 oz. coin - With 1.555 g platinum content, 1.556 g in weight, and 13.9 mm in diameter. 2. 1/10 ounce coin - With 3.11 g platinum content, 3.112 g in weight, and 16.5 mm in diameter. Also called fire assay, the method involves treating ores or alloyed metals under high temperatures and carefully controlled operations to separate gold from base metals (copper, zinc, or lead), which may be present in the ore. Once the base metals are heated at high temperatures, the gold (as well as the other precious metals that may be present) remains apart and the other non-precious metals react forming other compounds. This composition was meant to make the coins more durable and harder and thus resist dents and scratches, as, again, they were originally intended for circulation. On the obverse of the Krugerrand is the face of Stephanus Jonannes Paulus Kruger, fifth president of the South African Republic (note the surname Kruger and the South African currency Rand were combined to give this precious metal coin its name). General: Chemical Symbol: Os Atomic Number: 76 Category (as an element): Transition Metal Group/ Period/ Block (in the Periodic Table): 8/ 6/ d Atomic Weight: 190.23 g.mol-1 Electron Configuration: [Xe] 4f14 5d6 6s2 Physical: Density (near room temperature): 22.59 g.cm-3 Liquid Density (at melting point): 20 g. Silver: Silver compounds (example, colloidal silver), when absorbed into the body, may cause argyria, a condition characterized by the bluish-gray pigmentation of the skin, mucous tissues, and the eyes. While the condition is not really harmful to one's health, it is often permanent. Otherwise, silver per se is not at all toxic.