Of all the precious metals, gold is the softest, has the lowest tensile strength, and is tied with silver for the greatest ductility. Gold is one of only three colored metals. It combines easily with other metals to create alloys and thus can vary widely in strength and color. However, in contrast to silver, gold is extremely resistant to oxidation and most acids. It can only be chemically dissolved in a cyanide solution or strong oxidizing agent such as aqua regia. Gold can be easily cast, thanks to its low melting point for a precious metal. Its excellent ductility and workability, combined with its color variations in alloys, have predestined gold to play a key role in the production of jewelry and artwork. Its high electrical conductivity—topped only by silver and copper—in combination with impressive chemical stability are ideal prerequisites for utilizing gold in high-performance applications for the electronics industry. Gold primarily occurs with a valence of +3 in compounds, but occasionally +1 as well.The largest portion of available gold (approx. 60%) is fabricated into jewelry and pieces of art, where experts use it in a diverse array of alloys to give it the desired color and workability qualities. Another 35% can be found in the form of gold bars and coins in monetary institutions, or in the hands of private owners as an investment. Gold is particularly well suited to applications in the electronics industry due to its impressive electrical properties and resistance to corrosion.
