Platinum is a dense (heavy) hard silvery metallic element, a precious metal used in jewellery, coins, chemical engineering, and a catalyst used in industry and for car exhausts.
Atomic Number: 78
Atomic Weight: 195.08
Density or Specific Gravity: 21.45
Melting Point: 1768.90 Celsius
Hardness (Moh) 4.3
Historical Use
Platinum was used by the South American Indians before the fifteenth
century. They could not melt it, but developed a technique for
sintering it with gold on charcoal, to produce artefacts. A
pre-Columbian platinum ingot was found which contained 85% pure
platinum. When the Spanish conquered South America, they discovered the
Indians use of platinum, and called it "platina", a diminutive which
means "little silver", a somewhat derogatory term. It was considered by
the Spanish as a worthless nuisance and impurity.
Platinum is Used as a Precious Metal in Coins
Platinum Group Metals
Platinum is closely related to five other metals, palladium, ruthenium,
rhodium, osmium, and iridium. Together these six are known as the
platinum group metals, often referred to as PGMs. They all have
somewhat similar atomic structures, leading to some similarity in
chemical and mechanical properties, although there are, of course, many
important differences.
Platinum is a Good Choice for Diamond Mountings - Including Rare Natural Fancy Pink Diamonds
Processing
In about 1780, Janety was able to refine it using aqua regia, Smith
& Tennant developed an arsenic refining method after 1800, the
arsenic was used to aid in the melting. This was highly toxic and
dangerous, and it is not used nowadays.
Until about 1800, it was not realised that there were in fact six
different metals. Palladium was not separated and identified until 1803.
Platinum's melting point is very high, and consquently it is difficult
to melt. It was first melted by Lavoisier shortly after 1800.
Platinum Deposits
Until large deposits were discovered by Merensky at Rustenberg in South
Africa in 1924, 93% of the world's supply of platinum came from the
USSR. the Rustenberg deposits are considered very rich in platinum. The
ratio of platinum to palladium recovered is 2.5%!
Currently South Africa supplies around 70%, and Russia about 20% to 25% of the world's production.
Platinum in Jewellery
Platinum started to be used in jewellery in Europe about the mid
nineteenth century, but it was not until the 1924 find that it started
to become commonly used. It became very fashionable during the art deco
movement.
It possesses very good mechanical properties for jewellery, being
strong, and highly durable. It is ideal for stone settings as it has a
low "spring-back" rate.
In jewellery, like other precious metals it is mixed with other metals
to form alloys. Before 1975 there was no requirement for platinum to be
assayed and hallmarked in Britain, therefore there was no recognised
standard. Because of this, most early pieces marked "plat" or platinum,
may be of very variable, and quite low fineness, and most would fail
modern assay standards.
This also applies to many pieces marked "18ct & plat".
Platinum has been hallmarkable in Britain since January 1st 1975. From
then until January 1st 1999, the only officially recognised standard of
purity or "fineness" in Britain was 950 parts per 1000. From this year,
there are now four standards, which are:-
850
900
950
999
parts per thousand.
Typically platinum is alloyed with copper, iridium, palladium, cobalt,
ruthenium, tungsten, gallium or indium. It can also be alloyed with
rhodium, osmium or titanium but these are rarely used.
Platinum Wedding Ring in Matt & Polished Textures
Purest & Most Precious
Platinum has often been described as the purest, or the most precious
metal. Both these claims are slightly inaccurate. The "purest" claim
was based on the fact that the highest purity precious metal generally
recognised is sterling silver, at 925 parts per thousand (22 carat gold
is 916 parts per thousand), but this ignores the fact that Britannia
silver, 958 parts per thousand, has been a recognised standard in
Britain since 1796.
The price of pure platinum is generally higher than gold, but not
always, therefore the claim that platinum is the most precious metal is
also a typical marketing exaggeration, besides rhodium is frequently
double the price of platinum. As noted previously, the Spanish
conquerors of Latin America considered it a worthless nuisance.
Silver has its place in jewellery, particularly for larger and heavier
pieces, where its low price means it can be used lavishly. Silver does
tarnish very easily, and needs frequent cleaning, which is its major
drawback for jewellery. It was used for diamond settings in Victorian
gold jewellery, but has been superseded. Again its rapid tarnishing,
means it is less than ideal; it is also quite soft, and not durable
enough for diamond settings in general.
Certainly now that platinum has earned its recognition as a precious metal, silver is by comparison a poor relation.
For its combination of preciousness and purity, there is no doubt that
platinum deserves pride of place, so when we query the claim about
platinum being the purest and most precious metal, we are trying to
give an accurate honest appraisal on a completely objective basis.
Platinum Creates Strong Chains
Why is Platinum Expensive
Supply and demand is part of the
answer. In recent years, many new industrial uses for platinum have
emerged and grown. It is well known as a catalyst in many chemical
reactions, and is used in catalytic convertors for car vehicle exhast
systems.
Because of the high melting point, and the other difficulties in
extraction and refining, platinum is expensive to buy and process. This
includes higher labour costs for manufacturing it, and also higher
expense in recycling it.
We can supply any of our own designs in platinum on request.
More Platinum Chains
Platinum Firsts
Platinum was first used for coins in Russia in 1828.
In 1865 some Spanish gold coins were counterfeited using gold plated
platinum! Now the platinum fakes would be worth far more than gold
originals.
In 1907 Louis Cartier made the first platinum watch.
In 1975, hallmarking of platinum in the UK was started.
A Common Error
By the way, we frequently hear people, usually ones who think they know
what they are talking about, calling it "Platignum", which is a brand
name of pen.
This page was written by Lawrence Chard of Chard Coins, and is extracted from our "Plat" website. We hope you find this page useful and informative, please feel free to use the information we have provided, but please note we retain copyright on all contents including both textual content and images. Please do not copy our text or images without our prior written permission.
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