Diamond Designs and More

Precious Metals

 

Gold Gold

Gold is the most common precious metal used in high quality jewelry. Gold has a wonderful reflective property and can be polished to brilliant shine.  Furthermore, gold does not rust, corrode or tarnish, and hence the shine will not fade with time.

Two features are important to understand, when talking about gold quality: 

  • karat, the measurement of the purity of the true gold content,
  • alloys, the process of mixing gold with other metals to create varying gold characteristics

Platinum

Platinum has a lot in common with gold. Both metals are rare, very precious and  used in high quality jewelry. Like gold, platinum has a wonderful reflective property and can be polished to brilliant shine.  Furthermore, it does not rust, corrode or tarnish, and hence the shine will not fade with time. Platinum, however, is rarer than gold and more than twice as expensive.

The quality of platinum is defined in terms of its purity, yet different qualities of platinum may have different distinct purposes.


Internal link up to chapter Gold Karat

Karat (abbreviated as “k” or “kt”, and not to be confused with “carat” or “ct” which is the weight measure of diamonds and coloured gemstones) indicates the purity of gold on a scale of 1 to 24. 24 karat gold is the purest form of gold available, that is, it is 99.99% pure. 

Around the world, it has become common practice, and in some countries it is legally mandated, to indicate the purity of gold in jewelry by stamping a tiny mark on the jewelry (if space allows). In North America and Japan, the purity marks are stated in karat, e.g. 18K, 14K, 10K …, in Europe, the purity marks are stated in percentage, e.g. 999, 925, 750 …  Both methods are widely used in Asia and other parts of the world.

Alloys are mixtures of other more valuable and less valuable metals which are added to the gold to change its characteristics, such as hardness, colour and price.

The following table will define how the most common international gold markings are to be understood:

Gold Content Alloy (mix) content Percentage marking Karat marking

99.99%

0.01%

999

24K

91.66%

8.34%

925

22K

87.50%

12.50%

875

21K

75.00%

25.00%

750

18K

58.33%

41.67%

585

14K

41.67%

58.33%

416

10K

33.33%

66.67%

333

8 K

 

24K (999) Gold:
It is purest form of gold but it is too soft for everyday jewelry.  The gold can be dented, bent and scratched very easily. The colour of pure gold is a warm rich yellow.

21K (875) Gold:
This is mostly regarded as the highest quality to be used in jewelry. If the alloy contains 50/50 silver and copper, then it gives the metal sufficient stability and hardness to serve for jewelry purposes. 

18K (750) Gold:
In the West, this is usually considered the highest purity level and is used for the more expensive up-market jewelry items. White gold also usually has a maximum 18K purity

14K (585) Gold:
In the West, this is the most common level of purity, while in Asia this is considered the lowest grade of gold. It is usually hard, very durable and ideal for everyday wearing.  Non-gold alloys, however, may cause allergic reactions to the skin, in which case an ‘upgrade’ to 18K is suggested.

12K (500), 11K, 10K (416), 9K (375), 8K (333) Gold:
This low level of gold content is primarily used to reduce the price of gold used in jewelry. Due to a high non-gold alloy content, brilliant white gold can be made from this gold. This type of gold is only used in the West. 

In some cases, this gold purity is not the cheapest or mere low grade gold. If the gold is mixed with platinum or palladium to make white gold, this grade of gold can be very expensive. It may also have the effect of producing a hard platinum like metal, while being less expensive than platinum. In such case, gold is the alloy which is added to platinum to reduce the price of platinum.



Internal link up to chapter Gold Alloys:

Pure gold (24k or 999) is too soft to be used in everyday jewelry. Hence, jewelry gold usually uses an alloy metal to increase the gold’s hardness and change its colour. Palladium, platinum, rhodium, copper, zinc, nickel and silver are metals commonly mixed with gold for use in jewelry.

Alloys are a mixture of metals, which are added to the gold, to give it different characteristics:

  • to increase the gold’s hardness and improve wearability
  • to enhance the gold’s color – by adding a metal alloy the colour of gold can be changed from yellow to white, red, blue and even green gold. The most commonly used metals to alloy with gold are: Nickel, Copper and Silver.  Less commonly used are the Platinum metals, Rhodium and Palladium.
  • Nickel: - increases hardness and act as 'bleach' to give  the gold a  white colour
  • Copper: - reduces price, and gives gold a warmer and sometimes even a greener colour
  • Silver: reduces price and is used for making white gold. When using silver and copper in a 50/50 alloy, 18K gold is created, which is as hard as most 10K gold alloys. When increasing the silver content of the gold alloy, the gold will become softer and greener in shade.
  • Rhodium and Palladium: increase shine, whiteness, hardness and price.


Internal link up to chapter Platinum

Quality Features:

  • Pure Platinum is 95% platinum content (950) or higher and can be marked with the word ‘platinum’
  • Standard Platinum is 85 – 95 % platinum content (850 – 950) which is identified by an abbreviation such as “pt.” or “plat”
  • Platinum alloys must consist of 50% pure platinum content (950) and 50% of at least 950 purity platinum group metals (iridium, osmium, palladium, rhodium and ruthenium).

Uses of Platinum

  • Very elegant, precious, modern looking metal and when used with diamonds makes these look much more brilliant
  • Platinum and alloys of platinum, like pure gold, are hypoallergenic, meaning people having allergic reactions to nickel which is contained in white gold may prefer platinum or at least 18K (750) yellow gold jewelry
  • Platinum is harder and ber than gold, therefore it is sometimes used to strengthen settings using prongs

 

 
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