GOLD, the chemical element, is a dense, shiny, deep yellow precious metal. It has several qualities that have made it valuable throughout history, both as a medium of exchange and for decorative use as jewelry. It is attractive in color and brightness; it is so durable it's practically indestructible. Gold is also rare and usually found in nature in a relatively pure form. Gold is the most malleable and ductile of metals.
PLATINUM, is a heavy, malleable, ductile, precious, grey-white metal, is resistant to corrosion and occurs in some nickel and copper ores along with some native deposits. Platinum is used in jewelry, laboratory equipment; electrical contacts, dentistry, and automobile emissions control devices. Platinum's wear and tarnish-resistance characteristics are well suited for making fine jewelry. At WeddingBands.com, we use 95% platinum (950 Platinum) alloyed with 5% ruthenium to manufacture our wedding bands.
PALLADIUM, is a soft silver-white metal that resembles platinum. It is the least dense and has the lowest melting point of the platinum group metals. This metal also does not react with oxygen at normal temperatures (and thus does not tarnish in air). The largest use of palladium today is in catalytic converters. Much research is in progress to discover ways to replace the much more expensive platinum with palladium in this application.
RHODIUM, is extremely hard and bright, its primary use in jewelry is as a plating to give white gold extra shine. It also is sometimes used as an alloying agent for hardening platinum and palladium. Rhodium has both a higher melting point and lower density than platinum. It is not attacked by acids and only dissolves in aqua regia. It is one of the most expensive precious metals.
TITANIUM, Named for the Titans, sons of the Greek gods, Titanium, when pure, is a lustrous, grayish white metal. It has a low density, good strength, is easily fabricated, and has excellent corrosion resistance. It is mainly used in jewelry as an accent metal in Men's jewelry. Its inertness and ability to be attractively colored also make it a popular metal for use in body piercing.
COBALT, is an alternative metal, white color, harder than platinum, and similar to platinum appearance. Cobalt is not a precious metal. It is more scratch resistant than titanium and other precious metals. It can be sized slightly without cutting into the ring. The weights of cobalt rings are very similar to the weight of gold rings. Cobalt does not contain harmful alloys and as of today does not cause any allergic reactions.