Gold and diamonds are commonly known as rare and expensive metals around the world. However, few people realize that there are other metals that are much rarer and more expensive due to their unique and valuable uses. You will surely be surprised to hear their names and applications.
Top 10 Rare and Precious Metals in the World
Let’s explore the top 10 rare and precious metals in the world, measured in “troy ounces” – equivalent to 1.1 regular ounces or 0.031kg (1 ounce = 28.35g).
10. Indium
Pure indium bars.
Indium is a relatively rare, soft, malleable, and easily meltable metal that many sources claim to be non-toxic. It was discovered in 1863 by two German chemists, Ferdinand Reich and Hieronymous Theodor Richter. When bent in its pure metal form, it emits a crackling sound. Its primary application today is in the production of transparent electrodes used in liquid crystal displays (LCDs). It is also widely used in thin films to create lubricating layers.
Indium ranks 61st in abundance in the Earth’s crust, meaning it is three times more abundant than silver. It is primarily produced from the residues left after refining zinc ore. The demand for indium has rapidly increased in recent years with the popularity of computer and television LCD screens.
9. Silver
Silver jewelry
Since ancient times, this metal has been used in trade and as a foundation for various monetary systems. Today, in addition to its use in valuable decorative items, silver is utilized in many other fields such as dental prosthetics, electronic components, and the production of high-reflectivity mirrors. Particularly, its halogen salts play an important role and are widely applied in life; for example, silver nitrate is commonly used in film technology; or silver iodide can act as a cloud seeder for artificial rain.
Silver itself is non-toxic, but most of its salts are toxic and may cause cancer.
Silver has the ability to kill many types of bacteria and germs without leaving a clear impact on the health and lives of higher animals. Hippocrates, the father of modern medicine, wrote that silver possesses health benefits and disease prevention properties. In Vietnam, people have been known to wear silver for “wind protection” and “disease prevention“. Recent studies show that breast milk stored in silver-coated bottles spoils slower than that stored in conventional plastic bottles. Many manufacturers of refrigeration equipment such as Toshiba, Panasonic, and Samsung apply silver nano technology in refrigerators, air conditioners, and washing machines for sterilization purposes.
8. Rhenium
Pure rhenium bars.
Precious metals are ranked as such because they are hard to find and particularly difficult to analyze. The mining process for rare metals is always complex and expensive. For instance, a large amount of ore must be processed to extract just 1kg of the rare metal rhenium. This precious metal has strategic significance in the manufacture of high-temperature resistant machinery parts. With an extremely high melting point (over 3,000 degrees Celsius), rhenium alloys are used to create components in jet engines and rockets, and are ideal materials in the nuclear energy sector. Rhenium alloys with tungsten are used for light bulb filaments and thermoelectric batteries. Rhenium is also utilized as a catalyst in the refining and petrochemical industries.
Rhenium was discovered by scientists in 1925. Its name is derived from the name of the Rhine River in Germany (where it was discovered). In 2010, the metal had a price of about 141 USD/troy ounce (equivalent to over 4,500 USD/kg).
7. Palladium
The “younger sibling” of rhodium is palladium. This metal is also an essential component in automobile exhaust processors.
Palladium crystals
Palladium is a rare, silvery-white metal discovered by William Hyde Wollaston in 1803 and named after the asteroid Pallas. Notably, at room temperature and atmospheric pressure, palladium can absorb hydrogen up to 900 times its volume, making it an efficient and safe storage medium for hydrogen. Palladium also is highly resistant to tarnishing, has stable electrical conductivity, and possesses excellent chemical corrosion resistance, as well as good heat resistance.
The majority of palladium is used in catalytic converters in the automotive industry. In the early 2000s, due to concerns that automotive production could be delayed by a palladium shortage, Ford Motor Company stockpiled a large amount of this metal at nearly peak prices. As prices subsequently fell, Ford incurred a loss of about 1 billion USD.
The unique properties of palladium and other platinum group metals (PGM) explain their widespread use. About a quarter of goods produced today either contain PGMs or have PGMs playing a vital role in their production. More than half of the palladium and platinum supply is used in catalytic converters, where they convert up to 90% of harmful emissions from vehicle exhaust.
Palladium is found in many electronic devices such as computers, mobile phones, multilayer ceramic capacitors, soldering, low-voltage contacts, and SED/OLED/LCD televisions; it is also used in medicine and photographic technology.
It can also be used as a substitute for nickel in white gold production. Palladium is one of the three most commonly used metals to create alloys with gold in the production of white gold.
The mining company Nornickel (or Norilsk Nickel) from Russia is the world’s leading palladium producer, having extracted 86 tons of this metal in 2019. Northern Russia is the primary operational area of this company.
6. Osmium
Osmium crystals.
Osmium is one of the densest elements on Earth, discovered by Smithson Tennant in 1803. It is the best heat-resistant metal among platinum group metals (PGM), and in solid form, osmium has a slightly bluish-white color similar to zinc and is resistant to acids.
This metal is primarily used in stainless steel alloys for nibs of pens or tool hinge pins.
Recently, British scientists discovered that a compound of osmium and ruthenium has the potential to treat colon and ovarian cancer.
Researchers from the University of Warwick and Leeds found that the chemical properties of ruthenium and osmium are quite similar, and their atoms can combine with DNA fragments to destroy cancer cells. Using the compound of ruthenium and osmium can lead to the destruction of colon and ovarian cancer cells, including those that are resistant to the chemotherapy drug cisplatin.
In 2010, the price of 1kg of osmium was around 12,700 USD.
5. Iridium
Iridium is one of the rarest elements on our planet. It is a hard, silvery-white metal belonging to the platinum group (PGM), known for its excellent corrosion resistance, even at high temperatures of around 2000°C.
Iridium was discovered by Smithson Tennant in 1803 in England (the same year he discovered osmium). Although it is one of the rarest elements in the Earth’s crust, with an annual production and consumption of only 3 tons, it has numerous applications in specialized industries and medicine. Due to its unique properties, iridium plays a crucial role in medical fields, electronics, automotive industries, and in various consumer goods such as ballpoint pens, watches, and compasses.
Iridium spark plugs used in cars.
For instance, due to its high corrosion resistance, iridium is used in high-temperature semiconductor recrystallization crucibles, electrodes in chlorine production, and thermoelectric generators using radioactive isotopes in unmanned spacecraft. In the automotive industry, iridium is utilized as a spark plug material.
Iridium is primarily distributed in South Africa, and its average price is around $13,500/kg.
4. Ruthenium
Ruthenium was discovered and isolated by Russian scientist Karl Klaus in 1844. The name originates from Ruthenia, a Latin term referring to Rus, a historical region that today encompasses western Russia, Ukraine, Belarus, parts of Slovakia, and Poland. Karl Klaus named the element to honor his homeland.
A watch made of gold and ruthenium worth $70,000.
After a complex chemical process, this metal was isolated and used for various purposes. For example, ruthenium is added to alloys of palladium and platinum to enhance hardness and durability. It is also commonly used in the electronics field. In 2009, the price of this metal was approximately $14,500/kg.
Biologically, ruthenium can cause skin discoloration and may be carcinogenic and bioaccumulative in bones.
3. Gold
Gold is a yellow metal in bulk form, but when finely cut, it can appear black, ruby, or purple; it is soft, malleable, ductile, and reflective.
Gold combined with other metals produces various alloys with different colors, such as red when combined with copper, green when alloyed with iron, purple with aluminum, and white when mixed with platinum.
Historically, gold has often been viewed as beneficial for health; however, only certain salts and isotopes of gold have medical value. Modern science has shown that gold injections can help reduce pain and swelling from arthritis and tuberculosis.
Gold alloys have been used in dental restorations, particularly for crowns and permanent bridges.
Additionally, gold is used in food. Edible gold leaf, flakes, or dust is used in some gourmet foods as a decorative element. However, due to gold’s inert nature with all chemicals in the body, it adds no flavor or nutritional value.
Gold can be crafted into thread and is used in embroidery.
As gold is an excellent reflector of electromagnetic radiation, it is used as a protective coating for many artificial satellites, in infrared thermal protective sheets, and the helmets of astronauts. It is also utilized as a reflective layer on some high-tech CDs. McLaren uses gold leaf in the engine compartment of its F1 model.
Gold-plated objects always represent wealth and have a stunning beauty.
In the jewelry industry in Vietnam, the weight of gold is measured in “cây” (a local unit equivalent to ounces or taels) or “chỉ.” One “cây” of gold weighs 37.50 g.
In the global market, gold is typically measured using the troy weight system, where 1 troy ounce (ozt) equals 31.1034768 g.
The purity (or karat) of gold is measured on a scale of K (Karat). One Karat is equivalent to 1/24 of pure gold. Gold at 99.99% purity is equivalent to 24K. When we refer to gold as 18K, it corresponds to approximately 75% gold content. Currently, in Vietnam, gold is often traded in the form of bars, ingots, rings, chains, bracelets, and bangles, with gold content primarily at 99.999%, 99.99%, 99.9%, 99%, or 98%.
2. Platinum
Platinum is one of the rarest metals on the planet, with a gray-white color, high corrosion resistance, and a melting point of up to 3215°F. Platinum is used in jewelry, laboratory equipment, electrodes, medical and dental instruments, catalytic chemical devices, and in controlling emissions in automobiles.
Platinum is hypoallergenic, making it safe for individuals with sensitive skin.
A platinum clutch by jeweler Ginza Tanaka priced at €1,422,122.
The properties of platinum make it essential in many industrial sectors. Certain specialized products require the use of platinum, such as petrochemical refining, LCD screens, eyeglasses, cancer medications, paints, hard drives, fiber optic cables, and explosives.
The Japanese are particularly fond of platinum, consuming approximately 48% of the world’s platinum jewelry produced each year.
More than one-third of the platinum produced annually for international markets is used in toxic emission control systems for automobiles.
The price of the metal is about $40,000/kg (as of 2009).
Platinum mining and production are primarily concentrated in South Africa, which supplies about three-quarters of the world’s platinum demand. Anglo American Platinum, Impala Platinum, and Lonmin are leading global producers of platinum.
1. Rhodium
Rhodium, discovered by William Hyde Wollaston after he found palladium in 1803, is a silvery-white metal that is hard yet ductile. It has a high reflectivity and the highest electrical and thermal conductivity among all platinum group metals (PGMs). Rhodium does not oxidize in most aqueous solutions, including inorganic acids, even at high temperatures.
The primary use of rhodium is as an alloying agent with platinum, and in that form, it has various applications in the electrical industry and glass manufacturing.
In addition to its crucial role in the automotive industry, rhodium is also used to produce glass, mirrors, jewelry, electrical contacts, and turbine engines.
A fountain pen with a nib made from rhodium by Edison Pen Co showcasing the owner’s prestige.
Due to its very limited supply, rhodium’s price is extremely high, reaching over $10,000/oz at times in 2008. According to data from S&P Global Platts (UK), nearly 80% of the demand for rhodium and palladium comes from the global automotive industry. The richest rhodium deposits in the world are located in South Africa (a country in southern Africa), estimated to account for 80% of the world’s rhodium mining.
In comparison, about 2,500 tons of gold are produced each year, while the annual rhodium production is only about 1% of gold production, and its price is one and a half times that of gold.
