Gold is the oldest known metal to humans and is considered to be one of the world's most precious metals. Because of gold's wonderful properties beautiful lustre, it is considered to be one of the most important metals used for making jewellery.

• Pure gold is not reactive and is friendly to your skin. If you are experiencing any kind of of skin problem, it is likely that the gold has been combined with another type of metal, which is creating some type of allergic reaction.
• Gold can be shaped in any way. You can even create extremely thin sheets of gold.
  
• Gold purity is measured in terms of karat weight. Karat weight varies from 10k to 12,14 karat gold jewellery, 18, 22 karat gold jewellery and 24 k. The higher the karat number, the more pure the gold is. If you are searching for pure gold then you should pick 24 K gold. The rest of the karat weights have some type of metal mixed in. For example, 18 K gold jewelry contains 18 parts of gold and 10 parts another type of metal. 12 K gold is only 50% of gold.
  
• Pure gold is quite expensive and not really practical to wear since it is so soft. Because of that, it is combined with other metals, mainly silver and copper.
• To be called "solid gold", has to be at least 10 Karat.
• Gold is also mixed with other types of metal to change its natural yellow gold color. For example if you mix copper with the gold, your result is rose gold jewellery, while mixing the gold with silver leads to a more greenish color. There are a number of different gold jewellery designs you can create using the different colors of gold.
  

Gold purity is measured in Karats as well as in in terms of fineness (for European markings) Pure gold is 1000 fineness or 24 karats. It becomes easy to understand what a Karat is when you think of gold as an alloy or a combination of different metals. The karats then, characterize the percentage of pure gold that is in the alloy. So you can figure out the percentage of pure gold in any piece by dividing the karat by 24. For example 18K gold: 18/24=0.750. So that would be75% pure gold.

The table below explains this:

Karat           Parts Gold to Alloy    Percent Pure Gold    Fineness
            
 10K                        10/24                      41.67%                417                
 14K                        14/24                      58.33%                583                
 18K                        18/24                      75.00%                750                
  24K                       24/24                      99.99%                999                
                 
             
Anything that is less than 10-karat gold can not be legally marked or sold as gold jewelry within  the U.S.. The legal requirements for minimum content of gold vary greatly by country. For example, 9 Karat gold is popular in Englad, while 18k is the smallest allowable standard tol be referred to as gold in Italy, France and Switzerland.

The metal that gold is mixed with can strengthen the gold as well as change its color. This table below depicts the most common types of gold alloys and the metals that are combined with gold to making them.

          Color Of Gold             Additional Metals Used                
          Yellow Gold Jewellery      Copper, Silver                
          White Gold Jewellery       Nickel, Zinc, Copper                
          Green Gold Jewellery      Silver, Zinc, Copper                
          Rose Gold Jewellery       Copper, Silver               

When you are paying for solid gold, (whether its a neckace, bracelet, or gold ring jewellery) it is very important to ensure that is what you're actually getting! Pieces that are gold plated, bonded, or gold-filled will be much less expensive than solid gold. Things to watch out for when buying gold jewellery (unless you're specifically intending to purchase them), would be:

Vermeil - This is Sterling Silver that is Gold Plated.

Gold Plated - Sometimes called GP or KGP or RGP, these pieces have a really thin layer of gold that is electroplated onto their surface. Some other type of base metal is used underneath. Gold Plate pieces will always be less costly than Gold Filled pieces.

Gold Filled - Sometimes called GF or KGF, these pieces have a layer of at least 10 Karat gold that is mechanically bonded using heat and pressure to the surface of a supporting base metal. It is then rolled out to a specified thickness. The quantity of pure gold that is used is the reason why Gold Filled items always cost more than their counterparts which are gold plated.

To keep your gold jewellery looking as good and new as the day you bought it, a little time and effort is all that is required on your part. Gold is long-lasting and sturdy but it can scratch or dent if it is given rough treatment: Below is the most important steps in taking care of your gold jewellery:

1. Ensure that you remove all jewelry when you are doing physical labor or when you are handling harsh chemical products. The worst enemy to gold is chlorine, so be sure not to wear it while swimming in a pool or Jacuzzi.
2. It is usually the best idea to clean your gold jewellery using warm water, a mild soap ( but not a detergent), and a soft toothbrush. You can rinse it under warm running water and blot it dry using a soft cloth that is free of lint.
3. Store your gold jewellery in a fabric-lined box and keep it away from other jewellery pieces to keep it from getting scratched up.
   
4. From time to time,  look at your gold for signs of weakness or damage and bring it to a professional jeweler for repair immediately if you notice any deterioration on it. Your jeweler will be able to fix or preserve it for you.