page_title: Alloy
section_title: Precious-metal alloys
hierarchical_section_title: Alloy / History and examples / Precious-metal alloys
caption_attribution_description: Français&#160;: Nom de l'atelier&#160;: Sicile, Syracuse Métal&#160;: électrum Diamètre&#160;: 15,5mm Axe des coins&#160;: 8h. Poids&#160;: 3,62g Titulature avers&#160;: Anépigraphe. Description avers&#160;: Tête laurée d'Apollon à gauche, les cheveux longs&#160;; derrière la tête, une amphore. Description revers&#160;: Trépied delphien. Légende revers&#160;: SURAK-OSIWN Traduction revers&#160;: (de Syracuse).
context_page_description: An alloy is a combination of metals or metals combined with one or more other elements. For example, combining the metallic elements gold and copper produces red gold, gold and silver becomes white gold, and silver combined with copper produces sterling silver. Elemental iron, combined with non-metallic carbon or silicon, produces alloys called steel or silicon steel. The resulting mixture forms a substance with properties that often differ from those of the pure metals, such as increased strength or hardness. Unlike other substances that may contain metallic bases but do not behave as metals, such as aluminium oxide, beryllium aluminium silicate or sodium chloride, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, opaqueness, and luster. Alloys are used in a wide variety of applications, from the steel alloys, used in everything from buildings to automobiles to surgical tools, to exotic titanium-alloys used in the aerospace industry, to beryllium-copper alloys for non-sparking tools. In some cases, a combination of metals may reduce the overall cost of the material while preserving important properties.
context_section_description: Many ancient civilizations alloyed metals for purely aesthetic purposes. In ancient Egypt and Mycenae, gold was often alloyed with copper to produce red-gold, or iron to produce a bright burgundy-gold. Gold was often found alloyed with silver or other metals to produce various types of colored gold. These metals were also used to strengthen each other, for more practical purposes. Copper was often added to silver to make sterling silver, increasing its strength for use in dishes, silverware, and other practical items. Quite often, precious metals were alloyed with less valuable substances as a means to deceive buyers. Around 250 BC, Archimedes was commissioned by the King of Syracuse to find a way to check the purity of the gold in a crown, leading to the famous bath-house shouting of "Eureka!" upon the discovery of Archimedes' principle.
caption: Electrum, a natural alloy of silver and gold, was often used for making coins.
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