Gold

Name: Gold
Symbol: Au
Atomic number: 79
Atomic weight: 196.966569 (4)
Standard state: solid at 298 K
CAS Registry ID: 7440-57-5
Group in periodic table: 11
Group name: Coinage metal
Period in periodic table: 6
Block in periodic table: d-block
Colour: gold
Classification: Metallic
Melting point (1064.18?°C, 1947.52?°F)
Boiling point (2856?°C, 5173?°F)

 

Gold history:
People have been using gold to make jewelry since the Stone Age. Since the beginning of recorded history, gold has played a significant role in society. In the ancient world, gold ornaments were used in religious rituals symbolizing power, light and life. Archaeological digs suggest the use of Gold began in the Middle East where the first known civilizations began. The oldest pieces of gold jewelry Egyptian jewelry were found in the tomb of Queen Zer and that of Queen Pu-abi of Ur in Sumeria and are the oldest examples found of any kind of jewelry in a find from the third millennium BC. Over the centuries, most of the Egyptian tombs were raided, but the tomb of Tutankhamen was discovered undisturbed by modern archaeologists.
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What is gold?
Gold is a comparatively dense, shiny, yellow valuable metals in the world. There are many different ways to present the metal in jewelry, and the way that the metal is color and consistency can be manipulated to match almost any desire. Because pure gold is extremely soft, other metals are mixed with the gold to make the piece more durable, less expensive. Gold is extremely heavy metal. One cubic foot of gold weights half of a tone. Gold is rare. Gold is not effected by heat, air and moisture, it is also resistant to tarnish. All these properties make gold a valuable commodity. Gold is one of the heaviest metals. The Latin name for Gold is AURUM - which means morning blush - and from there it has got its chemical letters Au.
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Price of gold:
The Gold price is calculated on a daily basis on the big stock markets in London, Tokyo and New York, the price is $ / troy ounce. The price of gold jewelry depends on the jewelry design, purity of gold or karat weight and amount of the material needed for this particular item. The techniques of construction can make a piece more durable and flexible for added comfort. A well-made piece in a classic design will give you years of wear and enjoyment and, if cared for properly, will last a lifetime. Unique design, intricate details, gemstones or a special clasp may add to the price.
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Karat:
Nothing less than 10-karat gold can be legally marked or sold as gold jewelry in the United States. The legal requirements for minimum gold content vary widely country-by-country (e.g. 9 Karat is popular in Britain, while in France, Italy and Switzerland, 18k is the lowest permissible standard to be called gold).
Purity of gold is defined by its percentage. 100% pure gold is defined as 24 karat gold.
Too soft for jewelry 22 karat = 91.7% gold
Very soft — not recommended for jewelry 18 karat = 75.0% gold
Recommended for fine jewelry 14 karat = 58.3% gold
Not acceptable for jewelry 12 karat = 50.0% gold
The legal karat limit considered as real gold in the United States 10 karat = 41.7% gold

GOLD KARAT INFORMATION CHART

Karat Gold Parts Gold Percentage Gold Normal European Stamping
9 kt 9 in 24 37.50% 375
10 kt 10 in 24 41.67% 416
12 kt 12 in 24 50% 500
14 kt 14 in 24 58.33% 583 or 585
18 kt 18 in 24 75% 750
22 kt 22 in 24 91.67% 917
24 kt 24 in 24 99.99% 999 or .99999


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Stampings:
Most jewelry items made of precious metal are stamped with information about the purity level of the metal content. Generally the stamp is placed in an inconspicuous place on the item so it does not detract from the design. Stamps will usually be located on the inside of the band on a ring, on the post or basket setting on a pair of earrings, on the bail (the part that the chain slides through) on a pendant, and on the connecting ring or the clasp on a necklace or bracelet. Not all gold jewelry is stamped. Items that have been custom made or designed by your jeweler may not have a marking. This does not mean the items are not gold, they can still be tested by any jeweler, for gold quantity. A simple scratch test can be used. Some items, that have been sized or repaired, may also not be stamped as the stamping can be lost during polishing and finishing. There are several different abbreviations for Karat that should be known.
Abbreviation Meaning
YG or KY Yellow Gold
WG or KW White Gold
K or KT Karat

GP or KGP or RGP or Gold Plated

10k Also: --------16, 417, 10KP ------- 41.6% pure gold (10 parts out of 24) -------- Usually silver, copper, zinc, and nickel
14k Also: -------- 583, 585, 14KP -------- 58.3% pure gold (14 parts out of 24) -------- Usually silver, copper, zinc, and nickel
18k Also: -------- 750, 18KP -------- 75% pure gold (18 parts out of 24) -------- Usually silver, copper, nickel, and palladium (for white gold)
22k Also: -------- 916, 9179-------- 1.6% pure gold (22 parts out of 24) -------- Usually silver and copper
24kAlso: -------- 999-------- 100% pure gold (24 parts out of 24) -------- None
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Gold Alloys:
Gold alloys are always calculated by weight. For example 18 carat gold must contain at least 18 parts gold out of 24 parts total (75%). The proportions by volume can show a startling difference. There are many different combinations of metals which can be used to make gold alloys. Adding other metals to the mix also allows metallurgists to change the color of gold. Palladium or nickel can be added to create white gold. Adding copper produces a rose or pink tint, while silver gives gold a greenish cast. There is no such thing as red, pink, green or rose gold. The percentage of the other metals (copper, silver, zinc, and nickel) produces the different shades of gold. When jewellers speak of coloured gold, they mean coloured gold alloys. Gold itself is a yellow metallic element but, in its pure form, it is too soft to be used for general jewellery purposes, although there are some cultures which do wear pure gold jewellery, it would need to be heavily made and carefully used. It is usual for gold to be mixed with other metals to produce an alloy, which is simply a mixture of two or more metals. Most gold alloys are a mixture of gold, copper and silver.
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Gold Color:
Pure gold comes in yellow, but it can be produced in shades of rose, white, green, and even two-tone. Adding other metals to the mix also allows metallurgists to change the color of gold. Palladium or nickel can be added to create white gold. Adding copper produces a rose or pink tint, while silver gives gold a greenish cast.
Yellow Gold: Yellow Gold is the natural gold color. Pure gold mixed with silver and copper to retain the bright gold color.
White Gold: White gold is created by increasing the silver-colored alloys (zinc, silver, nickel) normally mixed with gold and decreasing the copper-colored alloys. 14K white gold contains as much gold as 14K yellow gold but is nearly white in color.
Rose Gold or Pink Gold: Pure Gold mixed with large percentage of copper in addition to silver and zinc to get the rose color. Estate rings made with rose gold or pink gold were made frequently in the "Retro Modern Jewelry Period." These period jewelry pieces are gaining new popularity.
Green Gold: Green gold is created by mixing an alloy of pure yellow gold and pure silver. For rings, harder metals such as nickel or zinc are sometimes added to make the gold more durable. The green color, like rose gold, is very subtle and is most noticeable when it is used in a piece of jewelry next to areas of yellow, white, and pink gold.
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Fools Gold:
Fools gold is not gold at all. It is a gold colored mineral found in other rocks like gold often is. It is really iron pyrite and in relation to gold is worthless.
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Clean jewelry:
Gold does not tarnish, but it can be dirtied or dulled by the oil in your skin, body lotion, makeup or other substances like soap. There are lots of products out there that promise to clean gold, but you can do it easily with mild detergent and a soft cloth. Tarnish can be removed with a commercial jewelry cleaner or with soap and water with a few drops of ammonia. Brush the cleaning solution into the gold with a small brush (you can use a toothbrush). After you have finished cleaning, simply rinse the gold with warm water and allow it to dry. You can remove grease from jewelry buy dipping it into rubbing alcohol.
Ultrasonic cleaners may be appropriate for some gold jewelry. Ask a jeweler to advise you before using this method, since certain pieces can be damaged by this cleaning method. Store jewelry separately so it does not scratch other jewelry. When doing household tasks such as gardening and cleaning, be certain to re move rings. Put your jewelry on after washing and applying any makeup/hair spray. Before doing high impact sports take off your jewelry as you may scratch the metal or chip the gemstones. Avoid storing your jewelry next to a heating vent, window sill or on a car dashboard.
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Jewelry Care:
If treated carefully the gold jewelry will last you forever. Always keep away your jewelry from chemicals such as chlorine and various cleaning fluids, causing it to appear less shiny. They are the worst enemies for gold. Do not wear your gold jewelry while bathing or cleaning. Gold is a very soft metal, easily scratched even by rubbing against other jewelry. Use a solution of warm water and detergent-free soap to clean your gold jewelry. Store gold items separately to prevent from scratching.
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Gold Filled:
If an item is described as "gold filled", or "gold overlay", that means that a layer of at least 10-karat gold permanently bonded by heat and pressure to one or more surfaces of a support metal, then rolled or drawn to a prescribed thickness. The karat gold must be at least 1/10 by weight of the total metal content.
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Gold Plated:
Gold Plated (GP or KGP or RGP) items have a very thin layer of gold electroplated to the surface of the item. They have some other type of (base) metal underneath. GP items are always less expensive than their Gold Filled counterparts.
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Tarnish Resistance:
18 carat alloys are almost completely resistant to chemical attack in normal use, whereas 9 carat alloys are much less resistant. Nine carat alloys for example will go dull or even black merely from exposure to chemicals in the atmosphere; they will also discolor in contact with perspiration, some fabrics, bleach and other household chemicals.
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Healing Power:
Today, medical uses of gold have expanded greatly. It is used in surgery to patch damaged blood vessels, nerves, bones and membranes. And it is used in the treatment of several forms of cancer. Injection of microscopic gold pellets helps retard prostate cancer in men. Women with ovarian cancer are treated with colloidal gold. And gold vapor lasers help seek out and destroy cancerous cells without harming