These are, in no particular order, gold, palladium, silver, rhodium, iridium, ruthenium, platinum, osmium, and rhenium. So that while the chemical element tellurium is considered one of the rarest element in the Earth's crust (its mass abundance being the same as that of rhodium, iridium, and ruthenium), its estimated price is only less than 5 U. The discoverers, John Deason and Richard Oates, found the nugget just a couple inches below the surface on a slope in a place that's sometimes called Black Reef. Records have the following details about the Welcome Stranger: Gross weight: 3,523.5 troy ounces (241.61 pounds) Trimmed weight: 2,520 troy ounces (172.8 pounds) Net weight: 2,315.5 troy ounces (158.78 pounds) Measurement: 2 feet (0.61 meter) x 1.02 feet (0.31 meter) For their find, Deason and Oates were paid about 19,068 by the London Chartered Bank (located in the town of Dunolly in Victoria), where they took the nugget. Spectrometry: This method is best used to assay platinum bullion or stock. With the use of a spectrometer or spectrograph, the amount or concentration of a given substance is assessed. The substances are identified through the spectrum they absorb or emit. This assay method has several types. These include absorption, fluorescence, X-ray, flame, visible, ultraviolet, infrared, photoemission, Mossbauer, nuclear magnetic resonance, and Raman. It ranks next to osmium in being the densest element. As to its main property, this is best expressed in its being considered the most corrosive resistant of all the precious metals. In fact, this is shown even in temperatures of as high as 2000 C (3632 F or 2273.15 K). Iridium was discovered in 1803 by the English chemist Smithson Tennant. cm-3 Melting Point: 3033 C, 5491 F, 3306 K Boiling Point: 5012 C, 9054 F, 5285 K Heat of Fusion: 57.85 kJ.mol-1 Heat of Vaporization: 738 kJ.mol-1 Atomic: Oxidation States: 8, 7, 6, 5, 4, 3, 2, 1, 0, -1, -2 Electronegativity: 2.2 (Pauling scale) Atomic Radius: 135 picometre Covalent Radius: 144 4 picometre Ionization Energies: 840 kJ. On the coin's obverse is a koala, in sunken relief (i.e., lowered from the coin's plane); on the reverse is Queen Elizabeth II. The coin has legal tender status in Australia. 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.