The rarest stable metal is tantalum. The rarest metal on earth is actually francium, but because this unstable element has a half life of a mere 22 minutes, it has no practical use.
In terms of abundance in the Earth's crust, the rarest metals are: gold, platinum, osmium, iridium, palladium, ruthenium, rhodium, tellurium and rhenium. These metals are different from Rare Earth Elements, which aren't actually rare in terms of abundance, but are rarely found in concentrated ore deposits.
1. Rhodium. Rhodium (Rh) is non-radioactive and is the most expensive metal in the world. It is a rare member of the platinum group with a global annual demand of 32 tonnes.
If translated into numbers, platinum—for all of its known deposits—is considerably more rare than gold and is the rarest metal of all. And it is, truly, a gift from the heavens.
Rhodium. Rhodium holds the title of being the most expensive precious metal on the planet.
Painite : Not just the rarest gemstone, but also the rarest mineral on earth, Painite holds the Guinness World Record for it. After its discovery in the year 1951, there existed only 2 specimens of Painite for the next many decades. By the year 2004, there were less than 2 dozens known gemstones.
"Platinum and Palladium Are 30 Times Rarer Than Gold."
Platinum in the Earth's crust originates from ultra-mafic igneous rocks. It can therefore be associated with rocks like chromite and olivine. In nature, pure platinum is unknown and well formed crystals are very rare.
Palladium is one of the rarest metals on earth and even more scarce than platinum – 15 times more rare to be precise. If all the platinum in the world fits in your house, then every ounce of palladium can easily squeeze inside your living room.
1. RHODIUM: TOP MOST VALUABLE METAL. Rhodium is the most valuable metal and exists within the platinum group of metals.
Platinum is the purest metal. Platinum is the only precious metal used in fine jewelry that can be 95% pure. Small amounts of iridium and ruthenium (a metal from the platinum family) are commonly added to platinum. The stamp will read PLAT , PT or 950.
Gold easily tops these numbers with a density of 19.3 g/cm3. However, this does not make it the heaviest element, and not even the heaviest precious metal, an honour which goes to platinum with a density of 21.45 g/cm³. The elements osmium, iridium, rhenium, neptunium and plutonium are also heavier than gold.
Of the nine precious metals, platinum is considered the most abundance with an abundance estimated to be . 003 parts per billion (ppb). The rest of the metals have a ranking from highest to lowest in terms of abundance.
As the ninth-most abundant element in the Earth's crust, titanium is relatively rare. Research shows the strong and lightweight metal only accounts for roughly 0.63% of the Earth's crust. With such little titanium available, it costs more to harvest and produce than other metals.
Rare. The abundance of tungsten in the Earth's crust is thought to be about 1.5 parts per million. Tungsten or Wolfram is considered to be one of the more rare elements.
The Gonneville deposit is estimated to contain 10 million ounces of palladium, platinum and gold – collectively called 3E (three elements) – plus more than 900,000 tonnes of base metals.
The average concentration of gold in Earth's crust is 'very, very low,' at 4 parts per billion. In its elemental form, gold is significantly rarer than diamonds.
Platinum – A Precious Metal of Choice
Naturally white, the rarest of precious metals and the most secure setting for diamonds and precious stones, Platinum is the perfect choice for an expression of love that will last a lifetime.
Palladium is regarded as of low toxicity, being poorly adsorbed by the body when ingested. It may cause skin, eye or respiratory tract irritation, may cause skin sensitisation. Liquid may cause burns to skin and eyes.
Currently palladium is the metal used in petrol vehicle catalytic converters, with about 2-7 grams per unit, depending on the vehicle in question.
Therefore, Cesium is the softest metal.
The scientists found Q-carbon to be 60% harder than diamond-like carbon (a type of amorphous carbon with similar properties to diamond). This has led them to expect Q-carbon to be harder than diamond itself, although this still remains to be proven experimentally.
As mentioned above, tungsten is the strongest of any natural metal (142,000 psi).