Precious Metal

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A precious metal is a metal with rare metallic chemical element and due to that high economic value. Precious metals are less reactive than most elements, have high luster, and have higher melting points than other metals.

Historically, precious metals were widely used in making jewellery, ornaments, idols, temples, currencies, and war equipments, but are now regarded mainly as jewellery, investment and industrial commodities. Following three metals are widely traded and considered as precious metals due to their rarity and beauty.

Metal is a solid mineral element that usually has a shiny surface and generally a good conductor of heat and electricity, and can be melted or fused, hammered into thin sheets, or drawn into wires. Metals form positive ions and basic oxides and hydroxides. Many metals are quite hard, with high physical strength. When polished, metals tend to be good reflectors of light. Common metals include bronze, copper and iron whereas metals used for making jewellery, such as gold, platinum, and silver are called ‘Precious Metals’.

Alloy is a mixture containing two or more metallic elements or metallic and nonmetallic elements usually fused together or dissolving into each other when molten. For example, brass is an alloy of zinc and copper. Metals easily form alloys with other metals. The presence of even a small amount of another element in a metal severely affects its properties.  

Rhodium

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Symbol: Rh
Electron configuration: Kr 4d8 5s1
Atomic number: 45
Melting point: 1,963 °C
Atomic mass: 102.9055 ± 0.00002 u
Discoverer: William Hyde Wollaston in 1804

Here Are 10 Facts About Rhodium...

• Rhodium is the most expensive precious metal
• The name Rhodium originates from the Greek word rhodon meaning rose. The first Rhodium compound discovered was a beautiful rose colour
• Rhodium was discovered by English chemist and physicist William Hyde Wollaston in 1803 in a platinum ore from South America
• It is obtained as a by-product of nickel and platinum production and is never found in mineral form, only being found in trace amounts within platinum or nickel ores
• Rhodium is commonly used in coatings and plating, electrodes for aircraft spark plugs, oil of rhodium, and in jewelry where it may be alloyed with platinum and or palladium
• Rhodium is resistant to tarnishing and corrosion and costs about six times as much as gold by weight
• 60% of the world’s rhodium comes from South Africa, and world production of the metal is only about 16 tons per year.
• Rhodium was made famous in 1979 when the Guinness Book of World Records awarded Paul McCartney a rhodium-plated disc to celebrate his status as history’s all-time best-selling songwriter and recording artist
• Rhodium is one of the rarest elements on Earth. Its abundance is estimated to be 0.0001 parts per million
• Rhodium was discovered, in 1804, by W. H. Wollaston, working in London at the time. Wollaston made a partnership with Smithson Tennant, in 1800, with the goal of developing and improving the technology of platinum refining. To one of the native platinum shipments from South America was applied an elaborated treatment. Mercury cyanide was added to the aqua regia platinum solution, the precipitate was removed and the resulting solution was evaporated. The residues were washed with alcohol, and the result was a dark-red material that was proved to be a sodium compound and a salt of a new metal. That salt would today be known as sodium chlorodite (Na3RhCl6.18H2O). This salt was heated up with hydrogen and was washed with water to remove the sodium chloride. The resulting residue was rhodium powder.  He chose the name rhodium (from the Greek rhodon, that means rose) due to the color of the chloride RhCl3 and of the respective aqueous solutions.

Silver

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• Silver kills bacteria by chemically affecting the cell membranes, breaking them down. Bacteria do not develop resistance to Silver, as they do to many antibiotics.
• The expression 'born with a Silver spoon in their mouth' stems from health rather than wealth status, as children fed with Silver utensils were believed to be healthier.
• Silver is the best conductor of heat of all elements. Its uses in solar panels and automobile rear window defoggers take advantage of this quality.
• Silver bullion coins have the highest degree of optical reflectivity of all bullion. A Silver mirror can reflect about 95% of the visible light spectrum.
• More than 2/3 of the Silver bullion produced worldwide is a by product of lead, copper and zinc mining.
• In the earliest Egyptian records, Silver was considered more precious than Gold.
• The name Silver originates from the Old English Anglo-Saxon word 'seolfor' meaning Silver.
• Argentina was named from Argentum, the element of Silver's Latin name.
• The word for Silver and money are the same in at least fourteen languages..
• In 1900, there were approximately 12 billion ounces of silver in the world. Today, that figure has fallen to about 300 million ounces of above-ground, refined silver.

Platinum

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Symbol: Pt
Electron configuration: [Xe] 4f14 5d9 6s1
Melting point: 1,768 °C
Atomic number: 78
Atomic mass: 195.084 u
Discoverer: Antonio de Ulloa in 1735

Here Are 10 Facts About Platinum...

• Platinum is the rarest and heaviest of the precious metals. All of the Platinum ever mined would fit in the average size living room.
• Annually, only about 133 tons of Platinum are mined, compared to about 1,782 tons of Gold.
• In contrast with Gold and Silver, there are no large above-ground Platinum Bullion stockpiles to protect against significant supply disruptions.
• Ten tons of ore and a five month process is needed to generate one ounce of Platinum Bullion.
• More than 90% of all Platinum supplies come from South Africa and Russia. Virtually all of the platinum mined in South Africa is committed to industrial contracts.
• Legendary jewelers such as Cartier, Faberge and Tiffany created their timeless designs in Platinum.
• The world's famous diamonds, including the Hope, Jonker I and Koh-I-Noor, are secured by Platinum.
• When World War II began, the U.S. government declared Platinum a strategic metal and its use in non-military applications, including jewelry, was disallowed.
• All Platinum Bullion coins are 99.95% pure and are available in one-ounce and fractional sizes. Investment-grade bars are also available in 10-ounce and smaller sizes from various producers.
• As with all precious metals (Gold, Silver, etc.), Platinum can be scratched. However, with Platinum, there is actually no material lost from the scratch as there is with Gold.

 

Palladium

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Symbol: Pd
Electron configuration: Kr 4d10
Melting point: 1,555 °C
Atomic number: 46
Atomic mass: 106.42 ± 0.01 u
Discoverer: William Hyde Wollaston in 1803

Here Are 10 Facts About Palladium...

• Palladium can absorb up to 900 times its own volume of hydrogen - the most common element in the universe.
• The largest use of Palladium is for automobile catalytic converters.
• In Japan, the government operates a specific mandate stating that all government-subsidized dental alloys have to include a Palladium content of at least 20 percent.
• Palladium alloys developed for jewelry typically contain 95% Palladium and about 5% Ruthenium.
• In 1967, Tonga issued Palladium general circulation coins commemorating the coronation of King Taufa Ahau Tupou IV, perhaps the first issue using Palladium.
• In the late 1800s, Palladium was more expensive than Platinum.
• Palladium is 12.6% harder and whiter in color than Platinum.
• Adding small amounts of Palladium alloyed with yellow Gold will yield the best and more durable white Gold.
• Palladium was first used in jewelry in 1939.
• Palladium is 30x rarer than Gold.

Gold

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Symbol: Au
Melting point: 1,064 °C
Electron configuration: [Xe] 4f14 5d10 6s1
Atomic number: 79
Boiling point: 2,856 °C
Atomic mass: 196.96657 ± 0.000004 u

Here Are 10 Facts About Gold...

• Gold is the only metal that is yellow or "golden". Other metals may develop a yellowish color, but only after they have oxidized or reacted with other chemicals.
• Nearly all of the gold on Earth came from meteorites that bombarded the planet over 200 million years after it formed.
• The element symbol for gold is Au. The symbol comes from the old Latin name for gold, aurum, which means "shining dawn" or "glow of sunrise". The word "gold" comes from the Germanic languages.  The pure element has been known since ancient times.
• Gold is extremely ductile. A single ounce of gold (about 28 grams) can be stretched into a gold thread 5 miles (8 kilometers) long. Gold threads can even be used as embroidery thread.
• A single ounce of gold can be beaten out into a sheet that is 300 square feet. A sheet of gold can be made thin enough to be transparent. Very thin sheets of gold may appear greenish blue because gold strongly reflects red and yellow.
• Although gold is a heavy, dense metal, it is generally considered non-toxic. Gold metal flakes may be eaten in foods or drinks.
• 24 carat gold is pure elemental gold. 18 carat gold is 75% pure gold. 14 carat gold is 58.5% pure gold, and 10 carat gold is 41.7% pure gold. The remaining portion of the metal usually is silver, but may consist of other metals or a combination of metals, such as platinum, copper, palladium, zinc, nickel, iron, and cadmium.
• Gold is a noble metal. It is relatively unreactive and resists degradation by air, moisture, or acidic conditions. While acids dissolve most metals, a special mixture of acids called aqua regia is used to dissolve gold.
• Gold has many uses, aside from its monetary and symbolic value. Among other applications, it is used in electronics, electrical wiring, dentistry, electronics, medicine, radiation shielding, and to color glass.
• High purity metallic gold is odorless and tasteless. This makes sense, since the metal is unreactive. Metal ions are what confers flavor and odor to metallic elements and compounds.