Due to its density, which is higher than that of gold, platinum is the strongest, heaviest and most durable precious metal, particularly suitable for everyday wear. Platinum’s long lasting durability and rich white color make it the perfect and most secure setting for diamonds and precious gemstones. As it is also the rarest of all precious metals, platinum is the symbol of powerful, everlasting and once in a lifetime love.
Platinum is naturally and permanently white in color, unlike white gold whose white color comes from alloys and rhodium plating that needs to be renewed from time to time so white gold can stay white. Platinum is also tarnish resistant and hypoallergenic, which gives it a great advantage over other precious metals. Over time, platinum develops a nice natural patina whose special silky shimmer is desired by many.
The high platinum value comes from its rarity; its presence is only 0.005 ppm (parts per million) in the Earth’s crust. It takes 10 tons of raw platinum to get one pure ounce of platinum. Each year, platinum is mined in quantities that are 15 times less than those of gold and platinum mines are only found in South Africa, Russia and North America. Platinum value is also related to its purity and its almost non-existent probability to wear down. Platinum jewelry usually contains 95% pure platinum and 5% of other metals or 90% pure platinum and 10% iridium. Platinum scratches do not result in metal loss, metal just shifts from one place to another, so platinum can be re-polished with minimum loss in metal weight.
Here is the list of four platinum alloys most commonly used in jewelry:
1. Pt900/Ir – made of 900 parts platinum and100 parts Iridium
2. Pt950/Ir – made of 950 parts platinum and 50 parts Iridium
3. Pt950/Ru – made of 950 parts platinum and 50 parts Ruthenium
4. Pt950/Co – made of 950 parts platinum and 50 parts Cobalt
Gold is a precious metal in great demand, very strong, but also highly malleable. Gold is a good electrical and thermal conductor, not prone to tarnish, corrosion and rust. The purity of gold is measured by karats or carats (K or kt) and caratage denotes the percentage of pure gold in a particular gold alloy. Pure 100% gold is 24K, very soft, extremely malleable and highly prone to scratching and damage. Due to these characteristics, pure gold is unfit for jewelry making and is thus alloyed with other metals for increased hardness. Two most popular gold caratages include 18K (75% pure) and 14K (58.3% pure), although 22K (91.7% pure), 10K (41.7% pure) and 9K (37.5% pure) are also used.
The color of pure 100% gold is yellow. It is also the most popular and most widely used gold color. However, the color of gold can vary depending on the type of metal that is alloyed with pure gold. Apart from yellow, other colors of gold include white, rose, purple, green, gray and blue.
Yellow gold is usually alloyed with copper and silver for increased hardness and endurance. 14K gold has a warm and bright yellow luster, whereas 18K gold has rich and deep yellow glow.
White gold is the alloy of yellow gold and either silver, nickel, manganese or palladium in addition to rhodium plating. To ensure white gold keeps its uniform white color, rhodium plating renewal is advised from time to time. White gold usually consists of 90% yellow gold and 10% of nickel, while copper may be added to improve malleability.
Rose gold is the alloy of yellow gold and copper. Depending on the amount of copper added, rose gold can vary from red to pink. 18K red gold consists of 75% yellow gold and 25% copper. 18K rose gold consists of 75% gold, 22.25% copper and 2.75% silver. Rose gold can acquire a yellowish tinge if no more than 15% zinc is added to the alloy of yellow gold and copper. The highest caratage for rose gold is 22K, which is also known as crown gold.