What is 18K Gold?
Most of the jade jewellery in our online store makes use of 18K gold and in this article, more information on this type of gold is provided.
Definition of 18K Gold
Firstly, 18K gold means 18 karat gold. The karat system here directly relates to the purity of the gold in relation to other metals within the gold alloy. 24K gold is the purest with a gold purity of 99.9%. All other variations, including 18K gold, are gold alloys. Pure gold is mixed with other metals to produce the various alloys and their purity directly relates to the numerical value in front of “karat”. 18K gold simply refers to a gold alloy with 18 / 24 parts gold. Thus, 18K gold has a gold purity of 75.0%. The remaining 25.0% of the gold alloy is made of different metals depending on the final colour required and also on the jewellery requirements.
Why 18K gold?
Pure gold is a very soft metal. Due to its softness, the metal is malleable and can be twisted and bent simply with one’s fingers. An example of this is in 24K necklace clasps. A common clasp used in 24K necklaces is closed simply by twisting the metal clasp shut with one’s fingers. 18K gold, having other different metals added to gold, is much harder. The hardness of the 18K gold depends on the type of metal added to the alloy but this added hardness provides a much needed benefit in jewellery setting. In setting jadeite jewellery, the hardier 18K gold helps provide a more secure setting to hold the jadeite and other adorning gemstones, adding additional durability to our jadeite jewellery pieces.
What are the various options of 18K gold?
18K gold is offered in 3 colour options in our online store: yellow, white and rose. These colour options derive from different metals used in the 18K gold alloy. The different colour hues are primarily used in jade jewellery setting to match various colours naturally present in Type A jadeite.
Other than pure aesthetic differences, an important point to note for white gold is that the pure white hue is achieved through a layer of rhodium, plated on top of the white gold alloy. This layer of rhodium is required because pure white cannot be achieved with gold alloys. At its best, a slight tinge of yellow persists in the final alloy used in white gold. Thus, a thin layer of rhodium is applied to achieve the pure white hue seen in 18K white gold. With time, this layer of rhodium will wear off and this is why 18K white gold becomes slightly yellowish. For 18K yellow and rose gold, the colour is achieved through the gold alloy compound and does not require any other metal plating. As a result, there is no change of colour with time.
How are 18K gold jewellery pieces maintained?
18K yellow and rose gold do not change in colour with time. Thus, for maintenance, it would simply be to keep the gold jewellery clean with proper frequent cleaning. With 18K white gold, the white rhodium plating will eventually wear away to display a slight yellowish tinge. This does not harm the gold jewellery in any way. However, if required, the pure white 18K gold can be restored with a quick and simple rhodium plating. This can be performed at any jewellery store. The existing 18K gold will be buffed to remove any surface imperfections and a new layer of white rhodium will be plated on top of the gold surface. Crucially, the buffing process might remove a thin layer of gold to ensure that the surface is completely smooth prior to the metal plating. As a result, repeated processes of wear and tear and subsequent buffing and plating do reduce the 18K gold, albeit very marginally.
Does 18K rose gold peel?
The colour in rose gold can be achieved through the mixing of gold and copper in an alloy. The resulting alloy has the rose colour which similar to 18K yellow gold, will not result in peeling of a surface layer over time. In some cases, peeling of the surface layer of rose gold is noticed. This however, is due to the rose gold colour being applied through plating of the original 18K gold. The underlying colour is revealed with wearing of the rose gold surface. In these instances where the jewellery is plated to rose gold, the re-plating of the surface layer is required to maintain the rose colour. This is similar to white gold.
In our online store, the 18K rose gold jewellery are not plated and thus peeling of the rose gold layer will not be an issue. Typically, if any specific colour hue is required, plating can be performed on request, but do keep in mind that the plated surface will wear away with time. Thanks for reading this article, and if you have any questions, feel free to reach us through WhatsApp or our online contact form. Thanks!