Table of Contents
Platinum is the ultimate luxury precious metal in modern jewelry. It was discovered late by Europeans during the 16th century and neglected at the time, because it was unknown to scientists and jewelers, who didn’t know how to refine nor work with it. Then it slowly (in three centuries) imposed itself as the precious metal of reference for jewelry during the 19th century and the beginning of the 20th century.
Although the general public knows little about platinum as a precious metal for jewelry, everyone knows that a platinum disc is a more rewarding than a gold disc. And platinum jewelry is much more expensive than gold jewelry, even when platinum price is inferior to gold price, quite strange don’t you think?
Platinum as a precious metal in jewelry took off at the 1867 Universal Exhibition in Paris during which the Mellerio jewelry house, a secular French jewelry store, exhibited a sublime platinum Tiara, which was acquired by the crown of Spain. Platinum then imposed itself as the precious metal of the Kings and princes of Europe.
View of the platinum tiara made by Mellerio and acquired by the Spanish crown since 1867
Platinum is a surprising and interesting metal in many ways, so much so that we have decided to deal with the subject in depth in order to help you choose your 950 platinum jewelry.
INDEX
- Composition and characteristics of Platinum
- History of its discovery
- Platinum Price
- How to recognize platinum
- Platinum hallmarks
- Platinum mining and extraction
- Platinum in Jewelry
- Famous Platinum Jewelry
1. Composition and Characteristics of Platinum
The chemical symbol for platinum is Pt (in jewelry too), it is a shiny gray-white colored metal that is very dense. With a density of 21.4 platinum is denser than pure gold whose density is 19.3 (pure platinum is 10% denser than pure gold). The density of 14 karat gold being 13.7; platinum is therefore 56% denser than 14 carat gold.
From left to right, Platinum 950, pure 24-karat gold, Pure silver
Its atomic number is 78, so it is placed next to gold (79) in the periodic table of the elements, which explains why it shares many chemical properties with pure gold.
Platinum is a transition metal obviously part of the platinum group which includes the following elements: Ruthenium, Rhodium, Palladium, Osmium, Iridium, Platinum and Rhenium.
Position of platinum in the periodic table of chemical elements
Physicochemical properties
Platinum is a precious noble metal that is both malleable and very ductile.
What does that mean ?
Platinum is a noble metal since it is unalterable, therefore it is not oxidized by oxygen and is not attacked by strong bases or strong acids.
Platinum is only attacked by aqua regia (HCL+HNO3), which dissolves it. We will detail this for the platinum acid test later.
Platinum is a malleable metal since it can be shaped easily in plate, cut with a saw, deformed by bending or hammering or even by stamping.
Platinum is a ductile metal since it can (just like gold) be drawn into wire very easily. It is estimated that one gram of platinum can be drawn into a fine wire over two kilometers in length.
Finally, platinum is a precious metal, since it is relatively rare and expensive and coveted, in the same way as the other precious metals which are gold, silver, palladium and rhodium.
Platinum is also and above all characterized by a very high melting temperature which is 3214°F (1768°C) compared with that of pure gold which is 1947°F (1064°C).
Finally, platinum resists friction and abrasion much better than gold, as platinum is 3 times more wear resistant than 18k gold, we will detail this later.
Platinum wedding band from our platinum jewelry collection
Platinum Black
Platinum black is a black porous platinum powder that is used in industry for chemical catalyst purposes and has no application in jewelry.
Platinum Formation
Where does platinum come from?
Before being extracted from the ground in mines, platinum comes from space. Like gold, platinum was formed during a supernova explosion by r-type stellar nucleosynthesis.
The iron atoms in the core of the collapsing star are subjected to a very strong flux of neutrons transmuting the iron into platinum and its isotopes (and other chemical elements).
Present in the protoplanetary gas cloud, it is then aggregated with the rest of the chemical elements of the cloud to form our solar system and the earth.
2. The Incredible History of Platinum
Although platinum has been discovered and worked by man for several millennia, it was only in the 16th century that it was first mentioned in Europe.
It was the Italian humanist Julius Caesar Scalinger who first mentioned platinum in 1557 in his work De subtilitate, ad Cardanum. He describes it as a mysterious Central American metal that is impossible to smelt:
“Præterea scitio, in Fundaribus, qui tractus est inter Mexicum, & Dariem, fodinas esse orichalci: quòd nullo igni, nullis Hispanicis artibus hactenus liquescere potuit. Adhæc non omnibus metallis uerbum, liquescere, uidemus conuenire.” P 134 (source).
Yet the oldest artifact made of platinum dates back to the days of ancient Egypt, dating back to 2700 BCE. Platinum was indeed found as decoration of the hieroglyphs on a decorative copper box found in the excavations of Thebes.
View of the ancient Egyptian decorative plate whose hieroglyphs are decorated with platinum, exhibited in the Louvres
It seems that this early and punctual use of platinum by the Egyptians was more accidental than intentional, the craftsmen of the time having been able to confuse platinum with electrum (an alloy of gold and silver).
Unlike the Egyptians, the pre-Columbian culture called La Tolita-Tumaco (from the name of the locality where it was established) used 100 years before our era, in a recurring way, alluvial platinum nuggets for the manufacture of artefacts and body jewelry.
Archaeologists have found many platinum nose jewels and platinum funerary masks in the tombs of this little-known culture, located in the west of present-day Colombia.
Location of the La Tolta-Tumalco culture, on the Colombian border with Ecuador
What is even more fascinating is that this culture did not have sufficient means of heating to melt pure platinum, which melting point is 1768°C. Therefore, it was by an artisanal method of sintering that the jewelers of this culture managed to make their platinum jewelry.
This technique consists of mixing platinum with powdered gold and melting the latter, then forging the ingot thus obtained. The operation is repeated a sufficient number of times so that the platinum is intimately mixed with the gold which then serves as a binder. The jewels obtained are for some platinum alloys with 60% platinum and 40% gold.
Example of a funerary mask made of a rich platinum alloy from the La Tolita culture (source)
Other Examples of Pre-Columbian Platinum Jewelry
View of a platinum nose ring of pre-Columbian origin
When the Spanish conquered America, they quickly discovered platinum in the gold and silver mines of the continent, as early as 1590 and pejoratively named it Platina (Small Silver), since they did not know this metal, and could do nothing with the European casting techniques available at that time. Indifferent to the jewels of the local populations and to the metallurgical techniques developed by them, the Platina was then literally thrown away with the mine waste and considered a nuisance.
Mines were even closed because of the excessive presence of this platinum, which could not be melted or separated economically from other metals. Here is the report made by Antonio de Ulloa to the King of Spain in 1748:
El interés de la corona española por el beneficio del platino y su comercialización a finales del sigle XVIII, Pedro Damian Cano Borrego, 2016.
Despite this, platinum aroused the interest of some chemists and counterfeiters during the 18th century, because it was very economical and almost as dense as gold. Therefore, some counterfeiters use it to mint fake gold-plated coins, which were difficult to identify at the time.
In 1758, the Spanish government decided to ban the platinum trade in order to fight counterfeiters.
In 1788, the Spanish crown decreed the royal monopoly of the platinum trade and set a compulsory state price and the obligation to platinum holders to sell it to the crown.
At the end of the 18th century, the French scientist Pierre Francois Chabaneau, working for the Spanish crown at the Seminary of Bergara, developed a method of purifying platinum to obtain an ingot that could be used for minting coins and making jewelry.
At the same time, the jeweler Marc Étienne Janety worked in platinum and made sumptuous platinum pieces, most of which have been lost. The most famous of these that have come down to us is the platinum sugar bowl commissioned by Louis XVI and made in 1786.
Louis XVI platinum bowl created by the jeweler Janety in 1786, exhibited in New York
Having fled to the United States in 1792 when King Louis XVI was deposed, he was recalled by the Convention in 1795 to create the reference units of weight measurement: the kilogram made of a mass of 1 kilogram of pure platinum which will be declared in 1799 the kilogram of the archives and which will remain for 90 years the reference weight before being replaced in 1889 by a weight of one kilogram in platinum-iridium.
If you ask yourself: Why choosing platinum to make such units reference? The reason is that Platinum is very stable in volume when temperature change, making it the perfect metal for such use.
The history of platinum is fascinating, and long, so I recommend reading this article on the subject.
The chronological history of platinum can be summarized by the following dates:
- 1200 BCE: Egyptians produce some gold jewelry containing traces of platinum from Nubia (now Sudan)
- 700 BCE: An Egyptian copper box is decorated with hieroglyphics made from an alloy of gold and platinum (intentional?)
- 100 BCE: the Tolita civilization repeatedly uses platinum to make jewelry and funerary masks
- 1557: first European written mention of the discovery of platinum in the Americas, in the region of Panama.
- 1590: discovery of platinum by the Spanish in the mines of Ecuador who denigrate it and call it Platina.
- 1748: the Spanish naval officer Antonio de Ulloa draws the attention of the Spanish authorities to the properties of platinum following his scientific expedition to Peru with the French Academie des Sciences.
- 1750: The Royal Society recognizes platinum as the eighth known metal following the presentation made by William Bronwrigg.
- 1758: French chemist Pierre Joseph Macquer achieved the first melting of platinum using a special oven. The same year, the crown of Spain prohibited the platinum trade.
- 1777: creation of the Bergara seminary in Spain to work on the purification of platinum under the direction of P.F. Chabaneau
- 1782: French chemist Antoine Lavoisier achieved the first melting of platinum with an oxygen-hydrogen torch, this method is not functional for large quantities of platinum
- 1783: Chabaneau perfects a process for forging platinum.
- 1786: creation of a platinum sugar bowl by the jeweler of the court of King Louis XVI, Marc Étienne Janety
- 1788: manufacture of a platinum Chalice in Spain, commissioned by King Charles III of Spain and offered to Pope Pius VI. The same year, the crown of Spain declared the monopoly (to its advantage) of the platinum trade
- 1795: creation in France of the metric system of weights and measures whose standard units are made of pure platinum by Janety
- 1819: Platinum is discovered in the Ural Mountains in Russia
- 1856: the jeweler Cartier buys several kilograms of platinum for the manufacture of platinum jewelry
- 1857: French chemist Henri Étienne Sainte Claire Deville develops a furnace for melting platinum and its alloys. He is notably the author of the book: “On the metallurgy of platinum and the metals that accompany it“
- 1912: France adopts the dog’s head as a hallmark to mark jewelry and objects made of platinum
- 1924: the largest platinum deposit in the world is discovered in South Africa, near Johannesburg by the German geologist Hans Merensky
3. Platinum Price
Although platinum jewelry is more expensive than gold jewelry and platinum is rarer in our societies than gold, its price has been lower than that of gold over the past 10 years, as shown this comparison chart.
Chart showing the price of one ounce (ouce troy is 31.10 grams) of platinum and gold in USD since 1985 (source)
As we can see, regardless of the scarcity of platinum on the market, its price varies, depending on supply and demand, independently of that of gold. This has been verified over time since the 1870s as this other graph shows.
Fluctuations in the price of an ounce of platinum and gold over the last century, in USD (source)
During the 20th century, the price of platinum was usually higher than that of gold.
It should be noted that platinum is mainly used by industry and that only 8% of platinum (platinum -rhodium – palladium) worldwide is used in the jewelry sector. It is therefore the industrial demand for platinum that controls the price of this precious metal, which is a vital industrial material for the automotive, military, space and fuel cell industries.
Breakdown of platinum uses by industry worldwide in 2021 (source)
Investment: platinum bullion
Like gold, platinum is a precious investment metal whose value, volatile over time, can be a safe haven for some. Platinum is available in bars of 1 gram, 10 grams, 100 grams, 1 kilogram from companies specializing in precious metal investments.
The interest of such an investment being to physically own the metal.
The disadvantage of Platinum on gold is that it is much less liquid and its resale is less easy than that of gold in the event of an emergency anywhere on the planet.
4. How to recognize Platinum ?
In order to recognize platinum in jewellery, when one does not rely on the platinum dog’s head hallmark on the jewel or when it is illegible, it is useful to know the characteristics of this metal, which make it possible to distinguish it from other precious metals.
Platinum vs Silver
Pure platinum has a specific gravity of 21.4 against a specific gravity of 10.5 for silver. Since platinum is almost twice as dense as silver, it is easy to see this and recognize the metal by weighing the jewel.
Silver is whiter and brighter than platinum, whose hue tends towards matt grey-white. In addition, platinum resists abrasion better than silver, this is clearly visible on an old piece of jewelry.
Platinum vs White Gold
18 karat white gold has a specific gravity of around 16 (which can vary depending on the alloy) compared to a specific gravity of 21.5 for pure platinum. In addition, rhodium white gold can be recognized by the extremely shiny and white rhodium layer on the surface, which is very easily scratched.
Palladium-plated white gold (not rhodium-plated) is whiter than platinum, which is grayer in color.
Platinum is much more resistant to abrasion than 18 carat gold.
Finally, white gold melts around 1000°C while pure platinum melts at 1768°C.
Platinum vs Palladium
Palladium is another precious metal used in jewelry for making rings and jewelry. It is a metal which is light gray and shiny, with a density of 12 g/cm3, palladium is almost half as dense as platinum, but its melting temperature of 1555°C is relatively close to that of platinum .
Platinum acid test
A simple and non-destructive method to recognize platinum is to test the jewel in question with acid, this is called the touchau method. Like gold, platinum is a noble metal unalterable by simple acids.
Like gold, platinum is only attacked and dissolved by aqua regia which is a mixture of concentrated nitric acid and hydrochloric acid.
The jewel is rubbed against a touchstone to leave a fine platinum mark on the stone. This trace is then treated with test acid by the jeweler who can then confirm, depending on the chemical reaction, whether the jewel is indeed made of platinum or other metals.
The touchau test is described in our article on the fineness of gold.
Views of a bottle of acid intended to recognize platinum by a touchau test
5. Platinum marks
Like all jewelry made of precious metals, platinum jewelry is hallmarked. This hallmark changes between France and abroad, according to the times and the French legislation is sometimes not very obvious.
We are going to take stock of the hallmarks of platinum in France and abroad.
Outside of France
In most countries of the world, platinum jewelry is identified by the Pt hallmark followed by the title of the platinum used. In the case of platinum 950, common in jewelry, the hallmark is the following Pt 950, this hallmark indicates that the jewel is made of Platinum 950/1000, i.e. 95% platinum and 5% other metals.
In France
It is by the decree of December 5, 1912 (and published on December 21) that the dog’s head hallmark is created in order to mark and identify French jewelry made in platinum whose title is at least 950/1000 . This hallmark will remain valid until 1994.
Illustration of the 1912 dog’s head punch for marking platinum jewellery, source Mike Fieggen author of the book Les bijoux des français
View of the decree of December 5, 1912 announcing the creation of the dog’s head hallmark for platinum works. Note that there is no mention of the purity of 950/1000 for the use of this hallmark
In 1994, the law relating to the guarantee of precious metals was amended by the law of January 4, 1994.
The modifications it implies for the marking of platinum jewelry are the creation of 4 hallmarks for 4 distinct titles of platinum, visible in this document from La Monnaie de Paris.
View of the various modern French hallmarks for marking platinum jewelry (see customs source document)
- The Penguin hallmark: is used for pure platinum bars of 999/1000
- The 1st title dog’s head hallmark: for works in platinum 950/1000
- The 2nd title dog’s head hallmark: for 900/1000 platinum works
- The 3rd title dog’s head hallmark: for works in platinum 850/1000
Let us recall in conclusion that these hallmarks of platinum are only valid for France and rather difficult to understand for all the other countries of the world.
6. Platinum mines and global platinum production
Contrary to popular belief, platinum is no rarer than gold in the earth’s crust. Since their respective clarke numbers are similar in the Earth’s crust, their abundance on Earth is of the same order of magnitude.
Here is a summary table of the abundance of precious metals in jewelry: Silver, Gold and Platinum as well as the tonnage of their respective annual production.
Metal | Symbol | Z | Clarke (ppm or g/t) | Production (2011) |
Silver | Ag | 47 | 0.07/0.08 | 23800 t |
Gold | Au | 79 | 0.003/0.005 | 2700 t |
Platinum | Pt | 78 | 0.003/0.005 | 192 t |
Abundance of precious metals on Earth (source)
What does that mean?
In the earth’s crust, platinum and gold are found at a concentration of about 0.003/0.005 grams per ton of rock.
The local concentration (expressed in grams of platinum per ton of ore) at ground level determines whether it is profitable to extract platinum or not. In platinum mines, this metal is found in a concentration of 2 to 20 grams per ton of rock, depending on the region.
However, the amount of platinum produced each year is almost 10 times less than gold and the amount of platinum in circulation worldwide is 20 times less than that of gold.
How to explain this difference?
While gold has been extracted from the ground by men for 6 or 7000 years, the exploitation of the first platinum mine began in an artisanal way in Colombia around 1750 (supposed date, no reliable source). It will be necessary to wait for the discovery of the first large deposit of platinum in Russia in 1819 to see the beginning of the industrial exploitation of platinum, that is to say barely two centuries ago.
In 2011, experts estimated the total amount of platinum already mined in the world at 9,400 tons compared to 200,000 tons for gold, or about 20 times less.
The distribution of platinum on the planet is very unequal and the main producer of platinum in the world is South Africa, which in 2021 accounted for 73% of world production, as this table shows.
Ranking of the main world producers of platinum (source)
Platinum Mines
The very first historical platinum mining site of Chocó located in Colombia now produces only one ton of platinum per year (source).
As for Russia, having the first historic site of industrial platinum extraction, it produces only 20 to 25 tons of platinum per year (source).
It is in the south-east of Africa, encompassing South Africa, Zimbabwe and Bostwana that the richest region in the world in platinum ores is found. This region accounted for more than 81.5% of global platinum production in 2021.
The Modikwa mine occupies the original site of the discovery of platinum ore by the German geologist Hans Merensky in 1924. It is the largest platinum mine in South Africa with estimated platinum reserves of 391/429 tonnes of platinum.
Note: estimating reserves from English measurements is confusing since there are two types of ounces: the 28.35 gram ounce and the 31.1 gram ounce (I admit that these imperial measurements lose me).
South Africa has 11 mining companies exploiting platinum and 30 active mines in operation (source). You will find information on most of these mining sites on this page. Most of them are located around the town of Rustenburg located 100 kilometers west of Pretoria.
These two maps show the location of platinum mines in South Africa and around the city of Rastenburg, this map is not exhaustive
This other map gives a better view of the identified platinum deposits in South Africa.
Platinum and PGM reserves
World reserves of platinum were estimated in 1997 at 56,490 tons (source), of which 50,000 tons are in South Africa. At the current rate of exploitation, there would therefore remain more than three centuries of platinum exploitation.
In general, the estimated reserves of PGM (platinum group metals) is 69,910 tons, 90% of which are still in South Africa, which makes this country the pivot for the world market. The slightest economic or political concern in the country would greatly affect world platinum prices.
Platinum Mining
Platinum is sometimes found in its native state, that is to say in the form of platinum nuggets. This was the case of the pre-Columbian mines of Colombia where the pre-Columbian peoples directly used the platinum nuggets they found in the ground to make their jewelry and masks.
Most often, platinum is mined associated with other metals (iron, gold, rhodium, iridium…) or in the form of platinum arsenide (PtAs2) or as a by-product of the exploitation of giant mines. copper or zinc, as is the case in most Russian mines.
Zoomed view of platinum arsenide (source)
This means that very important mechanical and chemical treatments are necessary in order to separate the platinum from the rocks extracted from the earth. Imagine that with a high concentration of 25 grams of platinum per ton, you have to extract and process 40 tons of rock to extract 1 kilogram of platinum.
Realize that it takes 2 to 6 months depending on the case to obtain pure platinum once the rocks extracted in South Africa have been processed in England. Here is a brief description of the process of extraction and purification of platinum.
It should be understood that platinum is not found alone in the rock, are also present most often gold, iridium, iron, copper and zinc. You have to separate all your metals from the rocks, but also from each other.
The rocks extracted from the mine are crushed and crushed before being washed, that is to say mixed with water and chemicals that will bind with the platinum (and the other metals present).
Air is pumped into this mixture in order to separate the metals by flotation by skimming the foam on the surface of the mixture, which foam contains a high concentration of platinum and PGM. This foam is dried and then contains 85 to 850 grams of platinum group metals per tonne.
This powder is then put in the oven in order to burn off the impurities which are then blown out, making it possible to obtain a concentration of 1.4 kilograms of PGM per tonne.
This is followed by an aqueous chemical treatment process to obtain 99.99% pure platinum. This process is summarized in the following diagram:
Simplified overview of the platinum refining process (source)
For those who are interested, the (almost) complete detail of the platinum refining process is described here.
7. Use of platinum in jewelry
The choice of platinum in jewelry is justified for customers by its brilliance, its particular brilliance and its unalterable and durable character.
For jewelers, it is the white metal of choice for setting diamonds and gems due to its mechanical resistance and its ductility and malleability, which makes it an easy metal to work on the bench peg.
It is also three times more resistant to abrasion than gold, which makes it a much more durable metal than the latter for all jewelry, but especially for making fine platinum chains. Indeed, while gold chains wear to the point of breaking due to friction, platinum chains are three times more durable than 18k gold chains and less likely to break over time.
However, platinum is a difficult metal to melt, which requires special equipment consisting of an acetylene-oxygen torch in order to reach a sufficient temperature for its melting and the production of platinum ingots.
Melting platinum is also not very obvious and requires special melting machines, operating under argon gas and under pressure of a few bars in order to ensure a good quality of melting, which however sometimes requires touch-ups by laser welding. These manufacturing concerns are the responsibility of the jeweler and do not affect the customers.
The benefits of platinum in jewelry are summarized here:
- Platinum is a noble metal, unalterable
- Ductile, it allows fine and light work
- Malleable, it is easy to shape for the jeweler
- Its natural color will never change over time and will require no maintenance.
- It is the most abrasion resistant of jewelry metals, your jewelry hardly wears out over time
- Its natural gray-white color highlights colored stones more than silver or white gold.
- The claw settings of your stones are more resistant than with gold
- Platinum is hypoallergenic and will suit those with general allergy concerns
- Platinum is the densest of the precious metals and is ideal for men wishing to wear a massive ring or signet ring.
Platinum Allergies:
Platinum does not generate allergy through jewelry. The only cases of platinum allergy concern people working in the medical field or exposed to platinum treatment processes and exposed by the respiratory tract to platinum salts (find out more).
Disadvantage with platinum:
Platinum is much more expensive in jewelry than the price indicated by the world price of platinum. I don’t have a quantified explanation to explain this. However, it should be noted that platinum wears out the cutting and rolling tools enormously, which must be adjusted to the platinum, this implies a limited work rate and premature wear of the platinum production tools in jewellery.
8. Famous platinum jewelry
Declared by Louis XVI, metal of Kings, platinum was initially reserved for European crowned heads who shared the privilege of owning the rarest of precious metals.
It was Cartier who first launched into the manufacture of platinum jewelry in 1856, democratizing platinum to the general public.
Here is a brief presentation of works of art and platinum jewelry that have made history.
Sugar Bowl Louis XVI, Platinum, 1786 |
Platinum chalice, Pope Pius VI, 1788 |
Platinum Watch, Cartier |
Platinum Brooch, Victorian Era |
For more information: