CTW – What Does it Mean When Talking About Diamond Jewellery?

What does CTW mean when discussing diamond jewellery?

The abbreviation CTW is applied to many things. But in a jewellery context this lesser-known abbreviation refers to “Total Carat Weight” for diamonds or gemstones. Written this way it accurately translates as “Carat Total Weight.”

Some jewellery features the three letters engraved or stamped into a ring with a number (the total carat weight) for the diamonds or gemstones. By doing this, some jewellery manufacturers can easily identify the gemstone weight of their jewellery.

What does Carat mean?

The word ‘Carat’ originates from a Greek word for the ‘Carab’ tree—seeds from which were used as a consistent weight measure. Regular sized Carob seeds consistently weigh close to 1 carat each with only a slight variation. This consistency contributed to their application as a reliable measure of weight. Read more about this on our dedicated Carat weight page. 

Diamond trilogy ring with ctw of 1.50 carats

Diamond Trilogy ring. This specific ring weighed 1.50 carats in total carat weight. 

Other letters appearing alongside CTW in jewellery

Alongside the total carat weight, there may be another letter such as ‘A’ or ‘G’

Approximate diamond weight

(A) – Might denote approximate. This refers to approximate carat weight. A diamond cluster ring might total approximately 1 carat of diamonds. In reality, the diamonds might really weight 0.99 carats or even 1.01 carats. Some jewellery manufacturers use this term to avoid having to be precise.

Guaranteed diamond weight

(G) – Sometimes denotes guaranteed diamond weight. Guaranteed diamond weight is typically around 1 point over the weight sold. For example, a 1-carat diamond trilogy ring will need a set of diamonds weighing 1.01cts at least to qualify as guaranteed carat weight.

Why apply a CTW total carat weight to an item of jewellery?

For anyone selling jewellery, it is important to specify the diamond weight of an item. Furthermore, it can be more difficult for carat weight to be determined when set into jewellery. For this reason, jewellery makers often add the carat weight into the shank of a ring. This appears in items such as diamond Trilogy rings and even diamond clusters made with many diamonds. Rather than the individual weight of the diamonds listed, the total carat weight is sometimes added for identification purposes.

Mark Johnson

About Mark Johnson

Mark attended Liverpool University and went on to pursue a career in the diamond industry. After more than a decade working in polished diamonds, Mark moved to the Isle of Wight where he launched Serendipity Diamonds. He works most days from their busy Ryde showroom, photographing jewellery and writing for the Serendipity Diamonds website. Anyone interested can connect with Mark on Linkedin via the profile link.

Mark Johnson

About Mark Johnson

Mark attended Liverpool University and went on to pursue a career in the diamond industry. After more than a decade working in polished diamonds, Mark moved to the Isle of Wight where he launched Serendipity Diamonds. He works most days from their busy Ryde showroom, photographing jewellery and writing for the Serendipity Diamonds website. Anyone interested can connect with Mark on Linkedin via the profile link.