Gold (Au)
 
 
Gold has long been a symbol of wealth in the form of expensive jewelry, coins and various works of art.   It also features incredible characteristics from a scientific point of view.   Gold standards have sometimes been used in monetary policies, but were widely supplanted by fiat currency starting in the 1930s.  The last gold certificate and gold coin currencies were issued in the U.S. in 1932.   In Europe, most countries left the gold standard with the start of World War I in 1914 and, with huge war debts, failed to return to gold as a medium of exchange.
 
Gold is a dense, soft, shiny, malleable and ductile metal.   It is a chemical element with the symbol Au (aurum in Latin, meaning glow of sunrise) and atomic number 79.   Chemically, gold is a transition metal and a group 11 element.   Gold has a bright yellow color and luster traditionally considered attractive.   It is a good conductor of heat and electricity and reflects infrared radiation strongly.   High quality pure metallic gold is tasteless and scentless, in keeping with its resistance to corrosion (it is metal ions which confer taste to metals).
 
It is unaffected by air, moisture and most corrosive reagents, and is therefore well suited for use in coins and jewelry and as a protective coating on other, more reactive, metals.   However, it is not chemically inert.    Being solid under standard conditions this metal occurs often in free elemental (native) form, as nuggets or grains in rocks, in veins and in alluvial deposits.   Less commonly, it occurs in minerals as gold compounds, usually with tellurium.   Gold resists attacks by individual acids, but it can be dissolved by the aqua regia (nitro-hydrochloric acid), so named because it dissolves gold.    Gold also dissolves in alkaline solutions of cyanide, which have been used in mining.    It dissolves in mercury, forming amalgam alloys; is insoluble in nitric acid, which dissolves silver and base metals, a property that has long been used to confirm the presence of gold in items, giving rise to the term the acid test.
 
The amount of gold in various alloys (a combination of gold and another metal such as silver) is measured in carats (k).   Pure gold is 24k.  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 (also in european jewelry 9k and even 8k is not uncommon), contain higher percentages of copper, or other base metals, silver or palladium in the alloy.   Copper is the most commonly used base metal, yielding a redder color.
 
Common colored gold alloys such as rose gold can be created by the addition of various amounts of copper and silver, as indicated in the triangular diagram to the right.   Alloys containing palladium or, more commonly, nickel are also important in commercial jewelry as these produce white gold alloys.   Less commonly, addition of manganese, aluminium, iron, indium and other elements can produce more unusual colors of gold for various applications.
 
Eighteen-carat gold containing 25% copper is found in antique and Russian jewelry and has a distinct, though not dominant, copper cast, creating rose gold.   Fourteen-carat gold-copper alloy is nearly identical in color to certain bronze alloys, and both may be used to produce police and other badges.   Blue gold can be made by alloying with iron and purple gold can be made by alloying with aluminium, although rarely done except in specialized jewelry.   Blue gold is more brittle and therefore more difficult to work with when making jewelry.
 
Fourteen and eighteen carat gold alloys with silver alone appear greenish-yellow and are referred to as green gold.   White gold alloys can be made with palladium or, more commonly, nickel.   White 18-carat gold containing 17.3% nickel, 5.5% zinc and 2.2% copper is silvery in appearance.   Nickel is toxic, however, and its release from nickel white gold is controlled by legislation in Europe.
 
Alternative white gold alloys are available based on palladium, silver and other white metals, but the palladium alloys are more expensive than those using nickel.   High-carat white gold alloys are far more resistant to corrosion than are either pure silver or sterling silver.   The Japanese craft of Mokume-gane exploits the color contrasts between laminated colored gold alloys to produce decorative wood-grain effects
 
As of 2011, it has been estimated that humans have mined around 171,300 tonnes of gold (GFMS).   This is roughly equivalent to 5.5 billion troy ounces or, in terms of volume, about 8876 m3, or a cube 20.7 m on a side.   The world consumption of new gold produced is about 50% in jewelry, 40% in investments, and 10% in industry.   Over the last 100 years South Africa has been the biggest producer of gold.   In recent times however it has been surpassed by China.
 
Besides its widespread monetary and symbolic functions, gold has many practical uses in dentistry, electronics, and other fields.   Injectable gold has been proven to help reduce pain and swelling in patients suffering from tuberculosis and rheumatoid arthritis.   Its high malleability, ductility, resistance to corrosion and most other chemical reactions, and conductivity of electricity led to many uses of gold, including electric wiring, colored-glass production and gold leafing.   Being the most malleable of all metals; a single gram can be beaten into a sheet of 1 square meter, or an ounce into 300 square feet.   Gold leaf can be beaten thin enough to become transparent.   The transmitted light appears greenish blue, because gold strongly reflects yellow and red.   Such semi-transparent sheets also strongly reflect infrared light, making them useful as infrared (radiant heat) shields in visors of heat-resistant suits, and in sun-visors for spacesuits.
 
Gold is very dense, a cubic meter weighing 19,300 kg. By comparison, the density of lead is 11,340 kg/m, and that of the densest element, osmium, is 22,610 kg/m.
 
 
 
 
 
 
 
GB Jewelers, Inc.
Under the Clock Tower
675 SE Marlin Avenue, Suite 1  /  PO Box 999
Warrenton, OR 97146
800-869-1481

Latitude:  46.159033 / Longitude: -123.9055280
 
 
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Monday - Saturday
 
Copyright 1974