Metal Education



Gold is a chemical element found on the periodic table with the chemical symbol Au and atomic number 79. Gold is a precious metal that has been used across the world for thousands of years. Throughout history there have been many purposes for gold, such a currency, statues, artwork, technology, and food embellishment. However, the most common use of gold has been for jewellery creation.

Gold jewellery never goes out of style, and for good reason. Gold can be worked into virtually any shape, including tiny strands that do not break easily. It its natural state it is a beautiful yellow metal that can be alloyed with other metals to produce a variety of colours.

Gold purity is denoted in two forms.

The Gold Karat System:

The Gold Karat System measures gold purity in fractions of 24. The number of karats refers to the content of the piece that is pure gold. The higher the number of karats, the purer the gold. 24 karats are the purest.
A gold karat mark includes a number followed by a K, KT, or Kt. Common gold karat stamps are 10K – 14K – 18K – 24K. For example, 18K means that the composition of metal is 18 parts pure gold (75%) and 6 parts alloys (25%).

The Millesimal Fineness Scale:

The millesimal fineness scale expresses purity in parts per 1000. A fineness mark is stamped as a three-digit number that indicates the percentage of pure gold in the item. The higher the number the purer the gold.
For example, 18K in this scale would be denoted as 750 which would indicate that the composition of metal is 75% pure gold and 25% alloys.

Yellow Gold

Calico - Yellow Gold - 9x7 mm Oval Solitaire Engagement Ring Mounting

In nature, Gold will always form naturally in its yellow colour. In its purest form, gold (24 karats) is soft and malleable, which is why alloys are often added to it to make it harder and more durable. Alloys are also added to change the colour of the metal to Rose, Pink, Green and White Gold.

Yellow Gold is a traditional and common metal used for jewellery production. Yellow gold has stood the test of time and remains a popular choice for jewellery. When polished there is no denying it’s classic beauty. Yellow gold is tarnish resistant which means that it’s colour will not overly fade with time.

Something to consider when choosing yellow gold is that not all yellow gold at the same karat will have the same colour. Because of the variety of alloys used, there can be slight variations in the colour of the metal. However, it is generally difficult to see the insignificant differences in colour.

White Gold

Calico - White Gold Ring - 6 mm Beveled-Edge Band with Milgrain - Size 10

White gold is an alloy of yellow gold and other white metals such as silver, nickel or palladium and gained popularity in the mid-1920s as a low-cost substitute for platinum. White gold can tend to have a yellowish hue due to high concentration of pure gold; however, it will often be plated with rhodium (a platinum metal) to give white gold a brighter white colour. Rhodium plating also acts as a protective layer, making gold jewellery more durable and resistant to scratches.

White gold is one of the most frequent metals used in jewellery. It is popular because the white colour of the metal increases the brilliance of stones, especially diamonds, increasing its scintillation (sparkling). White golds silvery hue complements other jewellery tones making it a great choice for those who are looking for an alternative to yellow gold.

Rose Gold

Calico - Rose Gold - Natural Diamond - Contour Wedding Band

Rose Gold is an alloy of pure gold and other metal alloys such as copper and silver. Rose gold came to fruition in the 19th century. Rose gold first appeared in the renowned Fabergé Eggs by famed Russian jeweller Peter Carl Fabergé.

When selecting rose gold keep in mind that rose gold is not hypoallergenic because of the copper alloy in it. If you are someone that has a sensitivity to copper, rose gold may not be the right fit for you.


Green Gold

Calico - Green Gold -  Accented Cathedral Shank

The classic mixture that produces green gold is an alloy of pure gold and pure silver. Harder alloy metals such as nickel or zinc are sometime used to produce a more durable green gold.

Green gold is most noticeable when it is used in a piece of jewelry next to yellow, white, or rose gold. Green gold was known to the ancient Persians as long ago as 860 BC under the name electrum, a naturally occurring alloy of silver and gold. The tops of some Egyptian pyramids were known to be capped in thin layers of electrum.