Platinum

Platinum is a naturally lustrous silvery white, and because of its beauty and hypoallergenic status is a sought after metal for jewelry. Platinum requires very little maintenance, as it is corrosion resistant and does not tarnish. It is also less malleable than gold. Platinum is the most expensive of the precious metals, due to stunning appearance and superior durability.

Purity

Pure platinum is too soft to be used for jewelry, however, it only needs to be mixed with a very small amount of other metals in order to be hard enough for jewelry. 

The purity of platinum is measured in 1000 parts and in general, the platinum used for jewelry has 950 parts of platinum and 50 parts of other metals. This means that platinum rings have a greater percentage of precious metal than the 18k gold rings which have 750 parts of gold and 250 parts of other metals. 

The most common metals to be mixed with platinum are palladium, rhodium, iridium and other platinum group metals.

Advantages & Disadvantages

Among all precious metals, platinum is the most precious, as well as the strongest and most durable. Platinum’s exceptional strength makes it ideal for holding gemstones.

Platinum also has the benefit of being hypoallergenic and beautiful. Its naturally white color never fades or becomes discolored. 

Although platinum is strong, it is prone to scratches and in rare cases can even be deformed if the ring is made too thin. 

Maintenance

Platinum only needs routine cleaning and polishing, unless it becomes scratched. Thankfully scratched platinum is relatively easy to repair. Jewelers are able to buff out small scratches and fill deeper ones with fresh platinum.

As platinum ages, it often develops a soft patina. This patina is a dull gray film caused by normal oxidation. This film changes the way that the platinum interacts with light and leaves the ring slightly darker than when it was new. The patina can be removed by regular polishing.

Silver

Fine silver is 99.9% pure. Silver is a bright, highly polishable metal that’s been used for currency, decorative objects, and jewelry throughout history, but not without support from other metals. On its own, silver is too soft for practical, everyday use. In order to use it in jewelry and other fine decorations, it's often mixed with other metals to create a more durable material known as sterling silver. 

Sterling silver is an alloy made up of 92.5% pure silver and 7.5% other metals, usually copper or zinc. Sterling silver pieces are stamped with 925 to mark their authenticity. Sterling silver is an alloy made mostly of silver and a small percentage of copper and zinc to strengthen it. It can last a lifetime and be passed on for many generations if properly cared for. Silver is soft and not as durable as sterling silver. It only contains .01% of trace elements. Silver is hypoallergenic, but sterling silver is not because it’s combined with zinc. Sterling silver is more easily tarnished than fine silver because of the other metals it contains. While 925 sterling silver is less “pure” than silver, it does not mean it’s not good.

Sterling silver is better than silver when designing and wearing jewelry because it’s stronger and can look good for a lifetime. Fine silver jewelry is easily damaged and not the best choice to wear on a regular basis. Sterling silver is also better for setting gemstones. Gemstones are too easy to lose in a 999 silver setting. 

Sterling silver does tarnish when gaseous compounds in the air containing sulfur contact the sterling silver and react creating silver sulfate, which leaves a dark coating or tarnish on the silver. Humidity, chlorine, make-up, cleaning products, and even the acid in your skin can all contribute to tarnishing. But tarnish isn’t permanent or a cause for concern - the piece can be polished to look like new.

However, while it is very affordable, silver is not suited to engagement rings because it is a very soft metal that bends out of shape easily. Silver is more suited to fashion jewelry that you wear occasionally. It simply cannot withstand a lifetime of wear and tear if worn daily on the hand.