Firstly, a bit about pure gold...
° In its purest form, it’s a yellowish, dense, flexible precious metal.
° It’s the most malleable of all metals.
° In its native form, it generally occurs as a nugget or a grain found in rocks, veins or in alluvial deposits.
° Most gold found, is believed to have occurred as a result of the asteroid impacts approximately 4 billion years ago.
° It’s one of the least reactive chemical elements, is solid under standard conditions and resistant to most acids.
° Currently, China is the largest gold mining country, and it is believed that approximately one-quarter of the world's gold production originates from artisanal or small scale mining.
° Gold has been used throughout history as coinage, in jewelry and in the arts.
° The purity of gold is measured in Karats (K). Pure gold is 24 karats.
WHAT'S THE DIFFERENCE BETWEEN 18 KARAT GOLD AND 9 KARAT GOLD?
Mainly, durability and color… Due to its softness, 24K (pure) gold is alloyed/mixed with other base metals to alter its hardness, durability and appearance. Gold with a lower karat ratings, such as 14K or 9K contain higher ratios of base metals such as Silver, Palladium, Nickel or Zinc in their alloy. 24K is pure gold in which one karat is 24ths of gold. Therefore…
9k Gold is 9/24 = 37.5% Gold
14K is 14/24 = 58.3% Gold
18K= 18/24 = 75% Gold, and so on…The ratio of alloy added, will affect the overall durability of the gold and the final color of the gold - 18K gold for instance, will be more durable and more Yellowy in color than 9K.
Did you Know... by law, gold must have a karat stamp, a hallmark, on it somewhere indicating its karat rating. Anything below 10K gold can not be sold as gold in the United States, though 9K and 8K old is sometimes sold as gold in other countries?
YELLOW GOLD, WHITE GOLD, ROSE GOLD... WHAT'S THE DIFFERENCE?
It’s all in the alloy that you add to pure gold.
° Yellow Gold – Naturally gold is “yellowish” in color and stable under standard conditions, meaning that it won’t tarnish, rust or corrode. However, as mentioned above, it’s still alloyed with some base metals to give it sturdiness when constructing jewelry. The more “yellow” a piece of gold the more pure but the less durable it will be. Generally, most jewelry is produced using 18K or 14K gold.
° White Gold – This is 24K gold alloyed with “white” base metals such as silver, palladium, nickel and sometimes zinc. The quantity of alloy added, will determine the karat rating of white gold and therefore, its final color. White gold is more durable than yellow gold, though will still have a yellowish hue. In some cases a piece of jewelry will be coated in a platinum based metal, known as rhodium plating (see below) to give the appearance of being completely “white”.
Its only real disadvantage is its not hypoallergenic and some people may react to some of the alloys. Rhodium plating the piece, can assist with this problem.
° Rose Gold – Is 24K gold alloyed with copper. The quantity of copper added will determine the karat rating of rose gold and therefore its final color. Rose gold or Russian Gold as it was once called is the most durable of all, as copper is very sturdy. As with white gold, some people may have an allergic reaction to rose gold as copper is not hypoallergenic.
RHODIUM PLATING OF WHITE GOLD
Rhodium is a member of the platinum metals family. Its silvery white in color, is hard wearing and hypoallergenic. It is often plated on to silver and white gold to give them a “white” color, adding a hypoallergenic coating and to prevent silver from tarnishing.
Over time this coating can wear off, especially on pieces worn regularly or exposed to certain chemicals such as cosmetics or perfume. This plating can be easily re-applied to keep the piece looking new and pristine.
WHAT IS GOLD PLATING AND GOLD FILLING? ... IS IT REAL GOLD?
° Gold Plating – or Electroplated as it is sometimes known, is when a piece of jewelry, generally costume jewelry produced out of lower grade metal such as silver or copper, is coated in a thin layer (a minimum of 2.5 microns thick) of lower karat Gold (generally 9 or 10k). The gold layer is bonded to that piece with heat. Over time this coating generally rubs off but can be re-coated again if necessary.
° Gold Filling – Similar to gold plating in that a layer of gold is mechanically bonded to the base metal of the jewelry, but it is constructed in a number of layers to an appropriate thickness. Gold filled jewelry is regulated in the US and the quantity of gold must make up one-tenth of the piece of jewelry to be considered gold-filled. They are more valuable than gold plated pieces, tarnish resistant, hypoallergenic and the coating will not rub/flake off.
KARATS OR CARATS?.... CARROTS?
Karats (K) are the units used for measuring the purity of gold. The Kartage System, measures it in fractions of 24ths, whereby pure gold is 24 Karats. Gold’s weight, is measured in grams.
Carats (Cts) are the units for measuring the weight of Diamonds and gemstones. One carat equals 200 milligrams (0.200 grams) or in simpler terms a fifth of a gram.
Carrots, delicious root vegetables and absolutely nothing to do with gold, jewelry or gemstones…
GOLD Vs PLATINUM
Platinum is the heaviest and densest precious metal, it’s stronger and more durable than gold. In the production of jewelry, platinum is generally alloyed with base metals and must have a minimum content of 50% platinum to classify as “Platinum Jewelry”. Platinum is hypoallergenic and rarer than any other of the jewelry making metals, carrying a symbol of prestige with it. Gram for gram, gold and platinum are similar in price, however, due to its density, platinum pieces of jewelry will weigh more, therefore increasing its total price.
WHAT IS PALLADIUM?
Palladium is a member of the platinum metals family and has always been used in the production of jewelry as an alloy to yellow gold. Recently however, it is now being used in its pure form to produce jewelry pieces and is being offered as another metal type to consumers. It received its own hallmark in 2009. It has a lower density than platinum but is almost as hard and has a similar “white” color. It has other added advantages in that it’s hypoallergenic and less expensive for a hard wearing metal.
Other Types of Gold
° Green Gold – Gold alloyed with silver.
° Blue Gold – Gold alloyed with iron.
° Purple Gold – Gold alloyed with aluminum.
° Black Gold – Gold that has been plated using black rhodium or ruthenium through electroplating