Precious metal
Overview
 
A precious metal is a rare, naturally occurring metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

lic chemical element
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...

 of high economic
Economics
Economics is the social science that analyzes the production, distribution, and consumption of goods and services. The term economics comes from the Ancient Greek from + , hence "rules of the house"...

 value.
Chemically, the precious metals are less reactive than most elements, have high lustre
Lustre (mineralogy)
Lustre is a description of the way light interacts with the surface of a crystal, rock, or mineral. The word lustre traces its origins back to the Latin word lux, meaning "light", and generally implies radiance, gloss, or brilliance....

, are softer or more ductile
Ductility
In materials science, ductility is a solid material's ability to deform under tensile stress; this is often characterized by the material's ability to be stretched into a wire. Malleability, a similar property, is a material's ability to deform under compressive stress; this is often characterized...

, and have higher melting point
Melting point
The melting point of a solid is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at standard atmospheric pressure...

s than other metals. Historically, precious metals were important as currency
Currency
In economics, currency refers to a generally accepted medium of exchange. These are usually the coins and banknotes of a particular government, which comprise the physical aspects of a nation's money supply...

 but are now regarded mainly as investment and industrial commodities
Commodity
In economics, a commodity is the generic term for any marketable item produced to satisfy wants or needs. Economic commodities comprise goods and services....

. Gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

, silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...

, platinum
Platinum
Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...

, and palladium
Palladium
Palladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired...

 each have an ISO 4217
ISO 4217
ISO 4217 is a standard published by the International Standards Organization, which delineates currency designators, country codes , and references to minor units in three tables:* Table A.1 – Current currency & funds code list...

 currency code.

The best-known precious metals are the coinage metals
Coinage metals
The coinage metals comprise, at minimum, those metallic chemical elements which have historically been used as components in alloys used to mint coins. The term is not perfectly defined, however, since a number of metals have been used to make "demonstration coins" which have never been used to...

 gold and silver.
Encyclopedia
A precious metal is a rare, naturally occurring metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

lic chemical element
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...

 of high economic
Economics
Economics is the social science that analyzes the production, distribution, and consumption of goods and services. The term economics comes from the Ancient Greek from + , hence "rules of the house"...

 value.
Chemically, the precious metals are less reactive than most elements, have high lustre
Lustre (mineralogy)
Lustre is a description of the way light interacts with the surface of a crystal, rock, or mineral. The word lustre traces its origins back to the Latin word lux, meaning "light", and generally implies radiance, gloss, or brilliance....

, are softer or more ductile
Ductility
In materials science, ductility is a solid material's ability to deform under tensile stress; this is often characterized by the material's ability to be stretched into a wire. Malleability, a similar property, is a material's ability to deform under compressive stress; this is often characterized...

, and have higher melting point
Melting point
The melting point of a solid is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at standard atmospheric pressure...

s than other metals. Historically, precious metals were important as currency
Currency
In economics, currency refers to a generally accepted medium of exchange. These are usually the coins and banknotes of a particular government, which comprise the physical aspects of a nation's money supply...

 but are now regarded mainly as investment and industrial commodities
Commodity
In economics, a commodity is the generic term for any marketable item produced to satisfy wants or needs. Economic commodities comprise goods and services....

. Gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

, silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...

, platinum
Platinum
Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...

, and palladium
Palladium
Palladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired...

 each have an ISO 4217
ISO 4217
ISO 4217 is a standard published by the International Standards Organization, which delineates currency designators, country codes , and references to minor units in three tables:* Table A.1 – Current currency & funds code list...

 currency code.

The best-known precious metals are the coinage metals
Coinage metals
The coinage metals comprise, at minimum, those metallic chemical elements which have historically been used as components in alloys used to mint coins. The term is not perfectly defined, however, since a number of metals have been used to make "demonstration coins" which have never been used to...

 gold and silver. While both have industrial uses, they are better known for their uses in art
Art
Art is the product or process of deliberately arranging items in a way that influences and affects one or more of the senses, emotions, and intellect....

, jewellery
Jewellery
Jewellery or jewelry is a form of personal adornment, such as brooches, rings, necklaces, earrings, and bracelets.With some exceptions, such as medical alert bracelets or military dog tags, jewellery normally differs from other items of personal adornment in that it has no other purpose than to...

 and coinage. Other precious metals include the platinum group
Platinum group
The platinum group metals is a term used sometimes to collectively refer to six metallic elements clustered together in the periodic table.These elements are all transition metals, lying in the d-block .The six...

 metals: ruthenium
Ruthenium
Ruthenium is a chemical element with symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most chemicals. The Russian scientist Karl Ernst Claus discovered the element...

, rhodium
Rhodium
Rhodium is a chemical element that is a rare, silvery-white, hard and chemically inert transition metal and a member of the platinum group. It has the chemical symbol Rh and atomic number 45. It is composed of only one isotope, 103Rh. Naturally occurring rhodium is found as the free metal, alloyed...

, palladium, osmium
Osmium
Osmium is a chemical element with the symbol Os and atomic number 76. Osmium is a hard, brittle, blue-gray or blue-blacktransition metal in the platinum family, and is the densest natural element. Osmium is twice as dense as lead. The density of osmium is , slightly greater than that of iridium,...

, iridium
Iridium
Iridium is the chemical element with atomic number 77, and is represented by the symbol Ir. A very hard, brittle, silvery-white transition metal of the platinum family, iridium is the second-densest element and is the most corrosion-resistant metal, even at temperatures as high as 2000 °C...

, and platinum, of which platinum is the most widely traded.

The demand for precious metals is driven not only by their practical use but also by their role as investment
Investment
Investment has different meanings in finance and economics. Finance investment is putting money into something with the expectation of gain, that upon thorough analysis, has a high degree of security for the principal amount, as well as security of return, within an expected period of time...

s and a store of value
Store of value
A recognized form of exchange can be a form of money or currency, a commodity like gold, or financial capital. To act as a store of value, these forms must be able to be saved and retrieved at a later time, and be predictably useful when retrieved....

. Historically, precious metals have commanded much higher prices than common industrial metals.

Bullion

A metal is deemed to be precious if it is rare. The discovery of new sources of ore or improvements in mining or refining processes may cause the value of a precious metal to diminish. The status of a "precious" metal can also be determined by high demand
Demand
- Economics :*Demand , the desire to own something and the ability to pay for it*Demand curve, a graphic representation of a demand schedule*Demand deposit, the money in checking accounts...

 or market value
Market value
Market value is the price at which an asset would trade in a competitive auction setting. Market value is often used interchangeably with open market value, fair value or fair market value, although these terms have distinct definitions in different standards, and may differ in some...

. Precious metals in bulk form are known as bullion and are traded on commodity markets. Bullion metals may be cast into ingot
Ingot
An ingot is a material, usually metal, that is cast into a shape suitable for further processing. Non-metallic and semiconductor materials prepared in bulk form may also be referred to as ingots, particularly when cast by mold based methods.-Uses:...

s or minted into coin
Coin
A coin is a piece of hard material that is standardized in weight, is produced in large quantities in order to facilitate trade, and primarily can be used as a legal tender token for commerce in the designated country, region, or territory....

s. The defining attribute of bullion is that it is valued by its mass and purity rather than by a face value
Face value
The Face value is the value of a coin, stamp or paper money, as printed on the coin, stamp or bill itself by the minting authority. While the face value usually refers to the true value of the coin, stamp or bill in question it can sometimes be largely symbolic, as is often the case with bullion...

 as money
Money
Money is any object or record that is generally accepted as payment for goods and services and repayment of debts in a given country or socio-economic context. The main functions of money are distinguished as: a medium of exchange; a unit of account; a store of value; and, occasionally in the past,...

.

Purity and mass

The level of purity varies from issue to issue. "Three nines" (99.9%) purity is common. The purest mass-produced bullion coins are in the Canadian Gold Maple Leaf series, which go up to 99.999% purity. Note that a 100% pure bullion is impossible, as absolute purity in extracted and refined metals is asymptotically
Asymptote
In analytic geometry, an asymptote of a curve is a line such that the distance between the curve and the line approaches zero as they tend to infinity. Some sources include the requirement that the curve may not cross the line infinitely often, but this is unusual for modern authors...

 approached. Historically, coins had a certain amount of weight of alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...

, with the purity a local standard. The Krugerrand
Krugerrand
The Krugerrand is a South African gold coin, first minted in 1967 to help market South African gold. The coin, produced by the South African Mint, proved popular and by 1980 the Krugerrand accounted for 90% of the gold coin market. The name itself is a compound of Kruger and rand, the South...

 is the first modern example of measuring in "pure gold"; it should contain at least 12/11 ounces
Troy ounce
The troy ounce is a unit of imperial measure. In the present day it is most commonly used to gauge the weight of precious metals. One troy ounce is nowadays defined as exactly 0.0311034768 kg = 31.1034768 g. There are approximately 32.1507466 troy oz in 1 kg...

 of at least 11/12 pure gold. Still more bullion coins (for example: British Sovereign) state neither the purity nor the fine-gold weight on the coin but are recognized and consistent in their composition, and many historically stated a denomination in currency (example: American Double Eagle
Double Eagle
A Double Eagle is a gold coin of the United States with a denomination of $20. . The coins are made from a 90% gold and 10% copper alloy....

).

Coinage

Many nations mint bullion coin
Bullion coin
A bullion coin is a coin struck from precious metal and kept as a store of value or an investment, rather than used in day-to-day commerce. Investment coins are generally coins that have been minted after 1800, have a purity of not less than 900 thousandths and are or have been a legal tender in...

s. Although nominally issued as legal tender
Legal tender
Legal tender is a medium of payment allowed by law or recognized by a legal system to be valid for meeting a financial obligation. Paper currency is a common form of legal tender in many countries....

, these coins' face value as currency is far below that of their value as bullion. For instance, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 mints a gold bullion coin
Gold coin
A gold coin is a coin made mostly or entirely of gold. Gold has been used for coins practically since the invention of coinage, originally because of gold's intrinsic value...

 (the Gold Maple Leaf
Canadian Gold Maple Leaf
The Canadian Gold Maple Leaf is the official bullion gold coin of Canada, and is produced by the Royal Canadian Mint. The brainchild of Walter Ott, it is one of the purest gold regular-issue coins in the world with a gold content of .9999 millesimal fineness , with some special issues .99999 fine...

) at a face value of $50 containing one troy ounce (31.1035 g) of gold—as of May 2011, this coin is worth about $1,500 CAD as bullion. Bullion coins' minting by national governments gives them some numismatic value in addition to their bullion value, as well as certifying their purity.

One of the largest bullion coins in the world is the 10,000 dollar Australian Gold Nugget
Australian Gold Nugget
The Australian Gold Nugget is a gold bullion coin minted by the Perth Mint. The coins have been minted in denominations of 1/20 oz, 1/10 oz, 1/4 oz, 1/2 oz, 1 oz, 2 oz, 10 oz, and 1 kg of 24 carat gold...

 coin minted in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 which consists of a full kilogram of 99.9% pure gold. There have been a small number of larger bullion coins, but they are impractical to handle and not produced in mass quantities. China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

 has produced coins in very limited quantities (less than 20 pieces minted) that exceed 260 troy ounces (8 kg) of gold. Austria
Austria
Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...

 has minted a coin containing 31 kg of gold (the Vienna Philharmonic Coin minted in 2004 with a face value of 100,000 euro). As a stunt to publicise the 99.999% pure one-ounce Canadian Gold Maple Leaf series, in 2007 the Royal Canadian Mint
Royal Canadian Mint
The Royal Canadian Mint produces all of Canada's circulation coins, and manufactures circulation coins on behalf of other nations. The Mint also designs and manufactures: precious and base metal collector coins; gold, silver, palladium, and platinum bullion coins; medals, as well as medallions and...

 made a 100 kg 99.999% gold coin, with a face value of $
Canadian dollar
The Canadian dollar is the currency of Canada. As of 2007, the Canadian dollar is the 7th most traded currency in the world. It is abbreviated with the dollar sign $, or C$ to distinguish it from other dollar-denominated currencies...

1 million, and now manufactures them to order, but at a substantial premium over the market value of the gold.

Economic use

Gold
Gold as an investment
Of all the precious metals, gold is the most popular as an investment. Investors generally buy gold as a hedge or harbor against economic, political, or social fiat currency crises...

 and silver
Silver as an investment
Silver, like other precious metals, may be used as an investment. For more than four thousand years, silver has been regarded as a form of money and store of value. However, since the end of the silver standard, silver has lost its role as legal tender in many developed countries such as the...

, and sometimes other precious metals, are often seen as hedges
Hedge (finance)
A hedge is an investment position intended to offset potential losses that may be incurred by a companion investment.A hedge can be constructed from many types of financial instruments, including stocks, exchange-traded funds, insurance, forward contracts, swaps, options, many types of...

 against both inflation
Inflation
In economics, inflation is a rise in the general level of prices of goods and services in an economy over a period of time.When the general price level rises, each unit of currency buys fewer goods and services. Consequently, inflation also reflects an erosion in the purchasing power of money – a...

 and economic downturn. Silver coin
Silver coin
Silver coins are possibly the oldest mass produced form of coinage. Silver has been used as a coinage metal since the times of the Greeks. Their silver drachmas were popular trade coins....

s have become popular with collectors due to their relative affordability, and, unlike most gold and platinum issues which are valued based upon the markets, silver issues are more often valued as collectables, far higher than their actual bullion value.

Aluminium

A precious metal that became common is aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

. Although aluminium is one of the most commonly occurring elements in the Earth's crust, it was at one time found to be exceedingly difficult to extract from its various ore
Ore
An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....

s. This made the little available pure aluminium, which had been refined at great expense, more valuable than gold. Bars of aluminium were exhibited alongside the French
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 crown jewels
Crown jewels
Crown jewels are jewels or artifacts of the reigning royal family of their respective country. They belong to monarchs and are passed to the next sovereign to symbolize the right to rule. They may include crowns, sceptres, orbs, swords, rings, and other objects...

 at the Exposition Universelle of 1855
Exposition Universelle (1855)
The Exposition Universelle of 1855 was an International Exhibition held on the Champs-Elysées in Paris from May 15 to November 15, 1855. Its full official title was the Exposition Universelle des produits de l'Agriculture, de l'Industrie et des Beaux-Arts de Paris 1855.The exposition was a major...

, and Napoleon III
Napoleon III of France
Louis-Napoléon Bonaparte was the President of the French Second Republic and as Napoleon III, the ruler of the Second French Empire. He was the nephew and heir of Napoleon I, christened as Charles Louis Napoléon Bonaparte...

's most important guests were given aluminium cutlery, while those less worthy dined with mere silver. Additionally, the pyramidal top to the Washington Monument
Washington Monument
The Washington Monument is an obelisk near the west end of the National Mall in Washington, D.C., built to commemorate the first U.S. president, General George Washington...

 is made of 100 ounces of pure aluminium. At the time of the monument's construction, aluminium was as
expensive as silver. Over time, however, the price of the metal has dropped; the invention of the Hall-Héroult process
Hall-Héroult process
The Hall–Héroult process is the major industrial process for the production of aluminium. It involves dissolving alumina in molten cryolite, and electrolysing the molten salt bath to obtain pure aluminium metal.-Process:...

 in 1886 caused the high price of aluminium to collapse permanently.

Bismuth and tellurium

Bismuth
Bismuth
Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a trivalent poor metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally uncombined, although its sulfide and oxide form important commercial ores. The free element is 86% as dense as lead...

 and tellurium are the only two metals which have abundances less than 10-8 by mass part (g/g) in the Earth's crust, but which are currently not of high economic value.

Rough world market Price ($/kg)s

Valuable metal Price ($/kg)s containing all precious metals names in bold
metal mass abundance Price ($/kg) 2009-04-10 Price ($/kg) 2009-07-22
0 0 0 0
Platinum
Platinum
Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...

5 ppb 42681 37650 49995
Rhodium
Rhodium
Rhodium is a chemical element that is a rare, silvery-white, hard and chemically inert transition metal and a member of the platinum group. It has the chemical symbol Rh and atomic number 45. It is composed of only one isotope, 103Rh. Naturally occurring rhodium is found as the free metal, alloyed...

1 ppb 39680 46200 88415
Gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

4 ppb 31100 30590 36370
Iridium
Iridium
Iridium is the chemical element with atomic number 77, and is represented by the symbol Ir. A very hard, brittle, silvery-white transition metal of the platinum family, iridium is the second-densest element and is the most corrosion-resistant metal, even at temperatures as high as 2000 °C...

1 ppb 14100 12960 13117
Osmium
Osmium
Osmium is a chemical element with the symbol Os and atomic number 76. Osmium is a hard, brittle, blue-gray or blue-blacktransition metal in the platinum family, and is the densest natural element. Osmium is twice as dense as lead. The density of osmium is , slightly greater than that of iridium,...

1.5 ppb 13400 12200 12217
Palladium
Palladium
Palladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired...

15 ppb 8430 8140 13632
Rhenium
Rhenium
Rhenium is a chemical element with the symbol Re and atomic number 75. It is a silvery-white, heavy, third-row transition metal in group 7 of the periodic table. With an average concentration of 1 part per billion , rhenium is one of the rarest elements in the Earth's crust. The free element has...

0.7 ppb 7400 7000 6250
Ruthenium
Ruthenium
Ruthenium is a chemical element with symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most chemicals. The Russian scientist Karl Ernst Claus discovered the element...

1 ppb 2290 2730 5562
Germanium
Germanium
Germanium is a chemical element with the symbol Ge and atomic number 32. It is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon. The isolated element is a semiconductor, with an appearance most similar to elemental silicon....

 
1500 ppb 1050 1038
Beryllium
Beryllium
Beryllium is the chemical element with the symbol Be and atomic number 4. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl...

 
2800 ppb 850
Silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...

75 ppb 437 439 588
Gallium
Gallium
Gallium is a chemical element that has the symbol Ga and atomic number 31. Elemental gallium does not occur in nature, but as the gallium salt in trace amounts in bauxite and zinc ores. A soft silvery metallic poor metal, elemental gallium is a brittle solid at low temperatures. As it liquefies...

 
19000 ppb 425 413
Indium
Indium
Indium is a chemical element with the symbol In and atomic number 49. This rare, very soft, malleable and easily fusible post-transition metal is chemically similar to gallium and thallium, and shows the intermediate properties between these two...

 
250 ppb 325 520
Tellurium  1 ppb 158.70
Mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...

 
85 ppb 18.90 15.95
Bismuth
Bismuth
Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a trivalent poor metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally uncombined, although its sulfide and oxide form important commercial ores. The free element is 86% as dense as lead...

8.5 ppb 15.40 18.19

External links


Organisations

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