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Precious metal alloys

Speaking about jewelry, we, first of all, mention the metal or alloy, which it is made of.

The manufacturing of jewelries is based on three metals — gold, silver and platinum. Having the unique features (beautiful color, softness, plasticity), these metals are used within the alloys for manufacturing of precious jewelries. The gold and the silver play the leading role here.

The precious metals are used in pure form very seldom in jewelry due to their lack of hardness and endurance, so the alloys of precious metals are used for manufacturing of jewelries. The other metals are added to the precious metals, in some proportions, in order to get the required properties. Such metals are called alloy or base metals. The base metals change the properties of the precious metals, i.e. render them harder and extend their life, change the color tone.

There are many jewelry alloys. The gold has the highest number of alloys and alloying constituents.

Influence of base components to the jewelry alloys

Gold alloys

The silver, copper, platinum, palladium, rhodium, zinc, cadmium, nickel etc. may be used as the alloying components with the gold. Each component influences on the properties of the alloy and its color.

Addition of silver to the gold, makes the alloy soft, ductile, reduces the melting temperature and changes the color of the gold. As far as the silver is added the color of alloy becomes greener and greener, turning into green-yellow; when the silver levels reach 30%, the color becomes yellow-white and pales as far as the contents of silver is increased; when the silver levels in alloy reach 65% the color of alloy becomes white.

The copper increases the hardness of golden alloy, while preserving its ductility and malleability. The copper in the golden alloy also influences its color. In such case the alloy gets the reddish tones, accentuated as far as the percentage of copper is increased; when the levels of copper reach 14,6%, the alloy turns red.

The platinum colors the golden alloy into white, the yellow tone is already lost at 8,4% contents of platinum in the alloy.

Silver alloys

Silver alloys has, as a rule, one base component — copper, but, sometimes the alloys of silver and zinc, cadmium, aluminum, nickel are used.

The copper increases the hardness of alloy, while preserving a sufficient plasticity, ductility and malleability. The copper within the alloy contents changes the color of alloy as well. As far as the copper contents increases, the color of alloy varies from white to red and yellow.

Platinum alloys

There are two platinum alloys used in jewelry, however the platinum contents is the same in both of them — 95%. Copper and iridium are used as the base components of these alloys. 5% of copper within the alloy reduces the melting temperature, while preserving the softness and plasticity. 5% of iridium within the alloy increases the melting temperature and hardness.

Color tones of golden alloys

The method of attribution of various color tones to the gold alloys is known since the old times. Historical facts — during the digging of Mycenae, the biggest center of Aegean art, the archeologists found a lot of golden articles: cups, diadems, masks, daggers, plated with the gold and silver. The inlaid work depicting various scenes of hunting was done with the high skill on the daggers. The old master used the silver and god alloys of pale yellow, dark yellow and white colors. They played the same role for inlaid work as the paints on the painter’s canvas.

The jewelry industry uses widely the alloys with various color tones now.

  • Red gold — necessary effect is achieved by addition of copper into the gold.

  • Yellow gold — alloy of gold with the silver and copper.

  • Green gold — alloy of gold with the silver or cadmium.

  • Blue gold — alloy of gold and steel.

  • White gold — alloy of gold and nickel or palladium, rarely with rhodium, platinum, zinc.

  • Purple gold — alloy of gold and aluminum.

The following components are added to render the gold alloys violet: aluminum, cobalt, palladium; brilliant black tone — silver or nickel and cobalt; pale olive color — tellurium.

No matter which base components are used to achieve the required color effect, the resulting alloy shall comply with the state standards on rate, i.e. the statutory proportion between the precious metals and base metals shall be preserved in it; the peculiar physical properties of precious metals shall be preserved as well.