Karat value and Vermeil

Karat value, vermeil and how these terms relate to electroplating

The terms karat value and vermeil are of particular significance to our customers who need to gold plate to the exacting standards their customers demand. Below is a breakdown of these terms, how they relate to our products and how you can take control of these quality standards to deliver for your customers.

Karat value and electroplating

When talking in terms of electroplating, karat value refers to the amount of gold in the gold deposit once plated. 1 karat represents about 4.17 percent gold purity and 24 karat is pure gold.

The metals making up common gold alloys are usually copper and silver. Gold alloys with a predominance of copper usually result in a reddish shade while those with silver produce gold with a greenish tint and in excess, a whitish-grey shade. Gold alloys containing both copper and silver can result in a yellow gold shade.

Using our products to plate to a specific karat value

If you need to plate to a specific karat value the best way is to use our mixing system. This system can only be used with our pen and brush plating kits and not with our tank plating kits.

Spa Plating’s mixing system, when used with our pen and brush plating kits, can be used to create the alloys and shades of gold commonly used in jewellery making and other crafts.

You can tank plate to a specific karat value with our Rose Gold Tank Plating Solution which deposits an 18 karat layer of gold. Our Yellow Gold Tank Plating Solution deposits a 22.5 karat layer of gold.

Our coloured gold mixing kit.


The term vermeil means a layer of 24 karat gold plate of at least 2.5 microns on sterling silver. It must cover most significant surfaces of the item and should be of at least 10 karat fineness.

For lower karat values of gold plate, the thickness to achieve a Vermeil layer increases in inverse proportion to the decrease of gold in the alloy. Therefore, if the gold content in the alloy has reduced from 24 karat to 18 karat (a reduction of 25%) then the thickness of plate needs to be increased by 25%. This means an extra 0.63 microns of gold has to be plated in addition to the 2.5 microns totalling 3.13 microns.

Using our products to plate to a vermeil standard

If you want to plate to vermeil standard, you will need to use our gold tank plating solutions and equipment, with specific reference to our online Plating Calculators.

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