Gold has been a highly sought-after precious metal for coinage, jewelry, and other arts since the beginning of recorded history. Gold is dense, soft, shiny and the most malleable and ductile pure metal known. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Gold is one of the coinage metals and has served as a symbol of wealth and a store of value throughout history.
Because of the softness of pure (24k) gold, it is usually alloyed with base metals for use in jewelry, altering its hardness and ductility, melting point, color and other properties. Alloys with lower caratage, typically 22k, 18k, 14k or 10k, contain higher percentages of copper, or other base metals or silver or palladium in the alloy. Copper is the most commonly used base metal, yielding a redder color. 18k white gold is 75% gold, 14k white gold is 58.3% gold, jewelry made from these metals has a slight yellow color.
Rose gold gets its color from a larger proportion of copper in the metal alloy. This gives the gold a beautiful pink color.
24 karat = 100% gold
Too soft for jewelry
22 karat = 91.7% gold
Very soft — not recommended for jewelry
18 karat = 75.0% gold
Recommended for jewelry
14 karat = 58.3% gold
Recommended for jewelry
10 karat = 41.7% gold
The legal karat limit considered as real gold in the United States
Silver is a very ductile and malleable (slightly harder than gold) monovalent coinage metal with a brilliant white metallic luster that can take a high degree of polish. Silver has long been valued as a precious metal, and it is used to make ornaments, jewelry, high-value tableware, utensils (hence the term silverware), and currency coins. Today, silver metal is also used in electrical contacts and conductors, in mirrors and in catalysis of chemical reactions.
Jewellery and silverware are traditionally made from sterling silver (standard silver), an alloy of 92.5% silver with 7.5% copper. In the US, only an alloy consisting of at least 92.5% fine silver can be marketed as "silver". Sterling silver is harder than pure silver, and has a lower melting point (893 °C) than either pure silver or pure copper.
As a pure metal, platinum is silvery-white in appearance, lustrous, ductile, and malleable. Platinum is a precious metal commodity; its bullion has the ISO currency code of XPT. Coins, bars, and ingots are traded or collected. Platinum finds use in jewelry, usually as a 90-95% alloy, due to its inertness and shine. In watchmaking, Vacheron Constantin, Patek Philippe, Rolex, Breitling and other companies use platinum for producing their limited edition watch series. Watchmakers highly appreciate the unique properties of platinum as it neither tarnishes nor wears out.