Platinum in Jewelry

Platinum is truly an eternal metal. Its purity symbolizes the purity of marriage. Its color is neutral - no need to worry about matching the right colors. Platinum is almost twice as dense as gold, it feels heavier and more substantial.
Platinum is closely related to five other so-called noble metals: palladium, ruthenium, rhodium, osmium, and iridium. Together these six are known as the platinum group of metals. They all have somewhat similar chemical and mechanical properties.
Platinum possesses very good mechanical properties suitable for jewelry. It is strong and highly durable. It is ideal for setting colorless diamonds - there is no color transfer from metal to the stone.

Platinum Chemistry

Platinum is a dense (heavy) hard silvery metallic element.

• Atomic Number: 78
• Atomic Weight: 195.08
• Density or Specific Gravity at 293 K: 21.45 g/cm3 
• Melting Point: 1772.0 °C (2045.15 K, 3221.6 °F)
• Boiling Point: 3827.0 °C (4100.15 K, 6920.6 °F)
• Hardness (Mohs scale) 4.3

Mixing pure platinum with various other metals (alloys) is a way to improve durability, hardness and malleability of platinum. Pure platinum is too soft to be used in jewelry although it might be used for settings of very fragile and very expensive gemstones such as emeralds and opals.  Platinum is commonly alloyed with ruthenium, palladium, tungsten, iridium, osmium, cobalt, iron or copper. A platinum content of 950 parts per thousand is required in the US and many other developed countries in order to mark jewelry simply "Platinum" without secondary metal qualifier. 

An alloy such as platinum/ruthenium is preferred for custom fabrication because of its exceptional properties. However, it is very difficult to cast because of its poor fluidity. Anybody using platinum alloyed with iridium is either not skilled in fine jewelry or using a lot of casting in his/her work. 10% iridium alloy is a sign of jewelry manufactured for mass market consumption.

History of Platinum

 Although platinum was used by the South American natives before the 15th century they could not melt it. Instead they developed a sintering technique - mixing it with gold using charcoal to produce artifacts. A pre-Columbian platinum ingot was found to contain 85% pure platinum.

When the Spanish conquered South America they discovered the natives' use of platinum and called it "platina" a diminutive which means "little silver." Spanish considered platinum to be a worthless nuisance and impurity. In fact, miners would often go around major veins of platinum while mining for gold. In the 18th century there were counterfeit gold coins made out of gold plated platinum.

Around 1780 platinum was refined using aqua regia. Smith & Tennant developed an arsenic refining method after 1800. This was highly toxic and dangerous. Until about 1800 people didn't realize that there were in fact six different metals. Platinum was finally melted around 1800 by Lavoisier. Palladium was not separated from platinum and identified as a separate metal until 1803.

Russia was supplying the world with more than 90% of it’s platinum until large deposits were discovered in South Africa in 1924. First platinum coins were struck in Russia in 1828. The use of platinum in jewelry in Europe was first reported at the court of Louis XVI of France, around the year 1780. In 1898, Louis Cartier introduced platinum jewelry into the world of snobby French jewelry. This would change forever the way in which diamonds are set. Platinum was unknown and was regarded as impossible to work with material. In 1907 Louis Cartier introduced the very first platinum watch. Widespread use of platinum jewelry dates from the late 19th to the early 20th centuries. It was particularly popular in the Edwardian Period jewelry (1901-1914).

Art Deco movement was a launching pad for platinum popularity and starting from that period platinum became the metal of choice for the finest jewelry up until World War II. During the war it was requisitioned for military use and temporarily substituted by white gold alloys. 

Today more than 70% of the world's platinum is consumed by industrial production and scientific research. Its high degree of electrical, thermoelectric and mechanical stability, and high level of resistance to heat and corrosion, have made important  for use in electronics, aerospace, precision engineering and car manufacture. Platinum is also irreplaceable in medicine such as in the manufacture of surgical instruments, implants, etc.