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Metal Facts
GOLD
Gold is one of the most precious metals in the world. It is found in the rivers, seas, and the earth’s crust. Approximately 3 tons of ore are needed to extract one ounce of gold. It’s rarity along with some desirable properties has made gold a popular metal for use in jewelry.
Properties of Gold
Gold in its pure state has a melting point of 1945 degrees Fahrenheit. 18K gold has a melting point of 1675 degrees Fahrenheit. The melting point varies depending on the alloy. 14K gold has a melting point of about 1550 degrees Fahrenheit, Again, the exact temperature is determined by the alloy.
Gold in its pure state is deep yellow in color. Its reflective property helps it keep its brightness and color from fading.
Gold in its pure state is more malleable than any other metal. Its unique ductility property allows it to be drawn into fine wire.
Gold in its pure state is softer than most metals. On the Mohs scale of hardness, gold has a hardness of 2 to 2.5. Diamond has a hardness value of 10.
Gold will alloy with many base metals. Different colors of gold result by alloying with different metals. Most frequently used alloy are nickel and copper.
PLATINUM
Properties of Platinum
Platinum is strong. It is the heaviest of the precious metals. It weights almost twice as much as karat gold.
Platinum jewelry commonly contains either 90% or 95% pure platinum.
Platinum is rare. Approximately ten tons of ore must be processed to produce a single ounce of platinum.
SILVER
Properties of silver
Silver is found in a native form, alloyed with gild or combined with sulfur, arsenic, antimony or chlorine in ores. The principal sources of silver are the ores of copper, copper-nickel, lead and lead-zinc.
Silver metal in its pure state has a brilliant white metallic luster.
Silver is a little harder than gold and is very ductile and malleable.
Applications of silver as a precious metal
1.Jewelry and silverware are traditionally made from sterling silver, an alloy of 92.5% silver and 7.5% copper. Sterling silver is harder than pure silver, and has a lower melting point (893 degrees C) than pure silver.
2.Coin silver ( a silver alloy) with 90% silver and 10% copper.
3.Dental alloys: Silver dissolves in mercury to make amalgams that are widely used for dental fillings. However, there is increasing evidence that the mercury in such amalgams may be absorbed by the body and can cause neurotoxicity.
4.Silver is also used in making solder and brazing alloys and electrical contacts.
5.Silver is used in high capacity silver-zinc and silver-cadmium batteries.
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