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Gold Part 13 |
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Rose Gold
Gold is known in different forms. Pink gold or red gold is one among them. It is also called rose gold. It was very famous in Russia in the nineteenth century and so it is also called a Russian gold. Rose gold is an alloy of gold and copper. It is mostly used for specialized jewelry because of its reddish color. The higher the copper content, the higher the red coloration. This gold is also used as a finish in bell interiors of musical instruments. It consists of a very thin plating of copper over a layer of silver and no actual gold is used.
Different carat alloys
22 karat rose gold is also known as crown gold. 18 karat rose gold may be made of 25% copper and 75% gold. 14 karat red gold is often found in the Middle East and contains 41.67% copper.
Black gold or 'grey gold' is another form of gold which is used in jewelry. Gold is known for its warm yellow color but it can be produced by various methods in differing colors ranging from white to black . Black colored gold can be produced by various methods as follows
- Electrodeposition or Electroplating using black rhodium or ruthenium. Solutions that contain ruthenium give a slightly harder black coating than those that contain rhodium.
- Patination by applying sulfur and oxygen containing compounds.
- Plasma assisted chemical vapor deposition process involving amorphous carbon, and controlled oxidation of carat gold containing chromium or cobalt.
More recently a laser technique has been developed that renders the surface of metals deep black.
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Gold Part 12 |
White Gold
A White gold is an alloy of gold and one white metal, usually nickel or palladium. The purity of white gold is also given in carats. The highest quality white gold is 18 karat, and made up of gold and palladium. Sometimes it is also alloyed with other metals like copper, silver and platinum for weight and durability.
White gold's properties vary depending on the metals and proportions used. This makes white gold alloys to be used for different purposes. A nickel alloy is hard and strong, and therefore good for rings and pins. Gold-palladium alloys are soft, pliable and good for white gold gemstone settings. Some higher-quality white gold alloys retain their shine and lustre, most will be coated with a very thin layer of rhodium
Chip Gold
Chip Gold is a gold ingot vacuum-sealed in a package in the shape of a credit card. It is meant to be used as a tangible and liquid investment in gold bullion. Weights available are 1g, 2.5g, 5 g, 10g, and 20g, 1/4 Ounce, 1/2 Ounce, 1 Ounce and the purity is 99% pure gold.
In Europe, Chip Gold is available in certain retail stores and from Goldas, a large jeweler and retailer worldwide. In North America, Kitco also has a line of Chip Gold. Also one can get the wafers through auction sites (eBay).
Colloidal Gold
Colloidal gold, also known as "nanogold", is a suspension of small-sized particles of gold in a fluid — usually water. The liquid is usually either an intense red colour or a dirty yellowish colour (for larger particles) The nanoparticles themselves can come in a variety of shapes like spheres, rods, cubes, and caps. The synthesis of colloidal gold was originally used as a method of staining glass. Due to the unique optical, electronic, and molecular-recognition properties of gold nanoparticles, they are the subject of substantial research, in a variety of areas, including electronics and nanotechnology
Skin irritation
White gold alloys made without nickel are less likely to be allergenic. One in eight person has a mild allergic reaction to the nickel in some white gold alloys when worn over long periods of time. White gold with nickel causes minor skin rash.
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Gold Part 11 |
Measure
The carat is a measure of the purity of gold in alloys. The word karat is used for the same in United States and Canada and the spelling carat is used to refer to the measure of mass for gemstones. This measure is abbreviated as ct or kt.
24-carat gold is the purest (99.9%) form of gold. 18-carat gold is 75% gold, 12-carat is 50% gold and so on. Nowadays, the carat system is increasingly being replaced by the millesimal fineness system in which the purity of precious metals is denoted by parts per thousand of pure metal in the alloy
The most common carats used for jewelry making and by goldsmiths are 24,22,20,18,15,14,10 and 9 carat gold. But the most common for jewelry making are 22 and 18 carat gold.
In olden days, in England the carat was divisible into four grains, and the grain was divisible into four quarts. A gold alloy of fineness (that is, 99.2% purity) could have been described as being 23-carat, 3-grain, 1-quart gold.
Derivation
The word carat is derived from the Greek kerátiōn meaning "fruit of the carob". Carob seeds were believed to have uniform weights and hence they were used on precision scales. However, later it was found that carob seeds have variations in their weights like other seeds. In the olden days, different countries each had their own carat, equivalent to carob seed.
Terminology
22/22K - a quality mark indicating the purity of gold, is very popular on the gold jewelry business in Asian countries like India, Sri Lanka, Pakistan, Bangladesh, Nepal, Yemen, and Persian Gulf countries. This symbol was most popularly used in India and was adapted and practiced by big jewelers. The first 22 signifies the "Skin purity" of gold jewelry and the second 22 signifies that after melting purity of the gold jewelry will be 22K (22 Karat) or 91.67% of pure gold.
This practice was introduced in the early mid-1980s in India, sparking a revolution in India. This practice forced jewelers to indicate correctly the after-melting purity, and increased consumer awareness.
In Chinese, Chuk Kam means pure gold, literally "exact gold". It is defined as 99.0% gold minimum with a 1.0% negative tolerance allowed. The quality of gold is guaranteed with a "Certificate of Gold" upon purchases in Hong Kong and Macau.
International carat ages of gold jewelry
Different countries use different carats of gold for jewelry making. Arabic countries and Oriental east countries like China, HongKong, Taiwan use 24 carat gold. Bangladesh, India, Pakistan and Srilanka mostly use 22 carat for jewelry. Persian Gulf region use 21 carat and 18 carat is mostly used in Egypt. European countries and USA use a range of 8-18 carats of gold and Russia uses 9-14 carat gold.
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Gold Part 10 |
Symbolism
Gold has been considered as one of the precious metals in the society and it has been associated with both evil and great acts throughout history. Credit card companies associate their product with wealth by naming and coloring their top-of-the-range cards "gold;" although, in an attempt to out-do each other, platinum has now overtaken gold. Though platinum has overtaken gold, it is still one of the much-valued metal among people. People purchase gold in sovereigns to show their prosperity and wealth. In some countries, it is a practice to send their daughters to their in-laws house with lots of gold jewelry to show their wealth and status.
In the Book of Exodus, the Golden Calf is a symbol of idolatry and rebellion against God. In Communist propaganda, the golden pocket watch and its fastening golden chain were the characteristic accessories of the class enemy, the industrial tycoons. In the Book of Genesis, Abraham was said to be rich in gold and silver, and Moses was instructed to cover the Mercy Seat of the Ark of the Covenant with pure gold. Eminent orators were compared with gold as person who has a "mouth of gold with a silver tongue".
Gold is associated with notable anniversaries, particularly in a 50-year cycle, such as a golden wedding anniversary, golden jubilee, etc. Great human achievements are frequently rewarded with gold, in the form of medals and decorations. Winners of races and prizes are usually awarded the gold medal and many award statues are depicted in gold.
Medieval kings were inaugurated with a sacred oil and a golden crown. The crown symbolizes the eternal shining light of heaven and thus a Christian king's divinely inspired authority. Wedding rings are traditionally made of gold; since it is long-lasting and unaffected by the passage of time, it is considered a suitable material for everyday wear as well as a metaphor for the relationship. In Orthodox Christianity, the wedded couple is adorned with a golden crown during the ceremony.
The value of gold varies greatly around the world, even within geographic regions. For example, gold is quite common in Turkey but considered a most valuable gift in Sicily.
Toxicity
Soluble compounds (gold salts) such as potassium gold cyanide, used in gold electroplating, are toxic to the liver and kidneys. There are rare cases of lethal gold poisoning from potassium gold cyanide. However, pure gold is non-toxic and non-irritating when ingested and is sometimes used as a food decoration in the form of gold leaf. It is also a component of the alcoholic drinks Goldschläger, Gold Strike, and Goldwasser. Gold is approved as a food additive.
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