Precious stones are held securely in settings made of the alloy and its white color harmonizes with diamonds, showing them to best advantage.

Although palladium is a modern jewelry metal, it has been used in settings for about twenty-five years-a setting being the small intricate part that holds a gem in jewelry. Makers of karat gold rings and other articles have used palladium settings for years, despite the fact that the jewelry palladium alloy is somewhat more expensive than 14K gold. The successful performance of the alloy in this service was the forerunner of its more general use in jewelry today.

In addition to its use in jewelry, palladium serves the public in many ways. Palladium is employed extensively for electrical contacts in numerous automatic controls that serve people every day in their homes, offices and factories. In these automatic devices, it is essential to have electrical contacts that will do an unfailing job over many years, without impairment of the contact-surface tarnishing and spark erosion. The drug manufacturers and the chemical industries utilize the excellent catalytic properties of palladium to produce more efficient antibiotics, cheaper vitamins and new chemicals.

RHODIUM

Pure rhodium is a white metal, much harder than pure platinum and palladium. This element melts at 3571 f. and weighs 0.447 lb. or 131 dwt. per cu. in.

Rhodium can be wrought, but it is used mainly as an electrodeposited coating on other .metals and for alloying purposes.

Reflectors for projectors and searchlights are rhodium plated to obtain a brilliant surface, not affected by heat or corrosion. Extensive use is made of rhodium plating to obtain a 'brilliant finish on jewelry, costume jewelry, novelties, lighters, etc. The hard finish can be obtained with a "flash" coating, less than 0.00001 in. thick, but thicker coatings are more durable.

As an alloying material, rhodium is used most frequently with platinum to produce alloys for use in equipment handling molten glass, rayon spinnerets, laboratory ware, thermocouples, gauze catalyst for nitric acid production, etc.

RUTHENIUM

Pure ruthenium is a hard, white, metallic element, melting around 4530°F. and weighing