ABOUT ESTATE PLATINUM JEWELRY
Platinum is in the ore family containing - iridium, palladium, osmiridium and ruthenium. Platinum, rhodium and palladium are the most frequent ores used in platinum jewelry.
Platinum is one of the heaviest metals used to make estate jewelry. The metal was first discovered in 1557. In the 1700's platinum was discovered in South America. The word platinum is derived from the Spanish word "plata", which means silver. The metal is found in gold bearing sand and in silver. Today's richest depostis are found in the former USSR, Canada, Colombia, Alaska, South Africa and the Congo.
Platinum was used very rarely until the late 1880s, because it takes such a high heat (1755C) to work with platinum and heating equipment was not adequate. During the 1920s, platinum became the most popular metal used in jewelry. Due to the popularity of platinum in the 1920s and the 1930s, white gold also became a popular metal for jewelry due to the similar appearance in the white nature of the metal.
Estate rings or antique filigree engagement rings made in the early 1940s are impossible to find, because platinum was restricted for use in the war efforts of WWII. Palladium was used frequently during these years. Palladium is a cheaper material and it does not weigh as much as platinum.
Estate jewelry made of platinum is very popular because there is generally very little show of aging or wear. The estate and antique filigree engagement rings of the 1920s and the 1930s were often made with platinum because of the durability of the metal.
Platinum is considered whiter in color than white gold and is more expensive than gold or silver due to its rarity. Platinum is heavier than 24KT gold by about 11% and is about 60% heavier than 14KT gold. Platinum does not tarnish, unlike silver. Rhodium is often used as a coating material, because it is a very hard metal. Rhodium is abbreviated Rh. Frequently sterling silver jewelry is coated with rhodium to strengthen the piece.
Many estate jewelry hallmarks will be PT900, indicating that the metal is 900 parts per 1000 of pure platinum. The remaining 100 part are usually made with iridium which makes the jewelry harder.
900 Plat - 100Irid - means platinum alloyed with 10% iridium.
PT850 - platinum at 85%
Pt also the chemical symbol - mark for platinum
PLATINUM - indicating mainly platinum
Platine - French or Canadian mark
Dog's Head - French mark indicating platinum used after 1912.
PT950 - platinum. Indicating that 950 parts per 1000 containing platinum. After 1973, The Hallmarking Act was initiated, which will now not allow jewelry to be marked platinum if it falls below 950 parts.
Many fine contemporary vintage platinum rings with precious gemstones such as tanzanite, sapphires, topaz and diamonds now available due to the popularity of the metal.