Platinum - the dethroned king of metals

It wasn’t until 1557, after the Spanish conquest of South America, that the first published references to a hard-to-melt metal, platinum, were noted by Italian scholar and poet, Julius Caesar Scaliger. Specimens of the metal were not received in Europe until the middle of the 18th century. The fact is, platinum had been worked by man, primarily for decorative purposes, for many thousands of years, particularly by the ancient Egyptians and the Incas. They just didn’t have quite as much of it as they had gold. Actually, all the platinum ever mined would only produce a cube 17 feet on each side, less than 5,000 cubic feet. Even with today’s modern placer mining methods, it takes up to 10 tons of ore to produce one ounce of platinum. Well-formed crystals of platinum are very rare and the common habit of platinum is nuggets and grains. Pure platinum is unknown in nature as it usually alloyed with other metals such as iron, gold, nickel, iridium, palladium, rhodium, ruthenium and osmium. These last five metals are collectively known as the Platinum Group and one of them, palladium, is traded as a commodity just like gold, silver and platinum.

Until 10 years ago, platinum reigned supreme as the world’s most expensive precious metal, but as the world recovered from the last big financial crisis, surprisingly, platinum not only lost its crown to gold, but at one point slipped behind palladium and the other Platinum Group Metals. However, in the minds of the general population, platinum is still top of the heap. A “Platinum Credit Card” is regarded as having a higher status than a Gold Card. A Platinum Record is one up on a Gold Record and Platinum Class is more expensive than Gold Class. Platinum is 20 times rarer than gold and 20% rarer than palladium. It is one of the densest metals being 11% denser than gold and almost twice as dense as silver. Its melting point is almost double that of silver too. Gold’s value is closely related to its safe-haven status in times of political and economic turmoil whereas platinum’s value is more aligned with its technological and scientific applications. At the time of writing, gold was fetching AUD$5,182.10 per ounce, whereas platinum was only fetching AUD$2,087.85 per ounce. Both are Troy ounces of which there are 12 to a pound.

A 701-gram nugget of platinum from Russia

The presence of other metals tends to lower the density of platinum from a pure metal specific gravity of 21.5 to as low as 14 and very rarely higher than 19 in natural specimens. The heaviest known substance is osmium, which has a specific gravity of 22.5, compared with gold which has an SG of 19.3. During the first 40 years of the 20th century, platinum was the preferred metal for wedding and engagement rings and was almost always used to enhance the beauty of diamonds and other gemstones. Just before World War II, platinum was declared a strategic material and its use in most non-military applications, including jewellery, was prohibited. During this time, white gold was developed as a replacement. Many people refer to platinum as “white gold” but they are incorrect. White gold is in fact an alloy of gold with white metals such as nickel, silver and palladium. For example, 18-carat yellow gold is made by mixing 75 per cent gold with 25 per cent of other metals such as copper and zinc. But 18-carat white gold is made from mixing 75 per cent gold with 25 per cent of nickel, silver or palladium. The amount of gold is the same but the alloy is different. And when white gold rings are new, they are coated with another white Platinum Group metal, rhodium, which is very white and hard but it does wear away eventually.

Notable occurrences of platinum include the Transvaal in South Africa; the Ural Mountains, Russia; Columbia; and Alaska, USA. Australia does have platinum, although it’s not a major producer on a global scale. While historically significant platinum deposits were found in Fifield, New South Wales, and alluvial deposits in Victoria, platinum is typically a byproduct of other mining operations, particularly nickel and copper. However, recent discoveries and exploration efforts are raising the profile of platinum in Australia.