The meaning of CTTW is something you’ll want to understand clearly before buying diamond jewellery. Knowing how it differs from ‘carat’ can spare you from the classic ‘what you ordered vs. what you received’ scenario, ensuring your purchase matches your expectations.
What Is CTTW?
The acronym CTTW stands for Carat Total Weight, a term you may have encountered when shopping for diamond engagement rings. It refers to the carat weight of all the diamonds in a piece of jewellery.
How Is CTTW Different From Carat?
Carat is the unit of measurement for the weight of gemstones – in this case, diamonds, while CTW in diamonds represents the combined carat weight of all diamonds in a jewellery piece. For instance, this peg head oval diamond classic engagement ring features a centre stone of 1.15 carats and additional accent diamonds of 0.16 carats (0.01 per diamond), coming up to a Carat Total Weight of 1.31. On the other hand, this oval diamond solitaire classic engagement ring, featuring just one diamond, has a carat size of 1.15, which is equal to its Carat Total Weight.
So, the definition of CTTW in diamonds would be – the sum of the individual carat weights of each diamond, whether it’s a single diamond or many smaller ones.
Is CTTW Only for Diamonds?
The simple answer: Yes, the meaning of CTTW mostly applies to diamonds, and here’s why.
Say you’ve got your eyes on a piece of coloured gemstone jewellery featuring diamonds like this emerald-cut ruby hidden halo classic engagement ring. The CTTW here only applies to the diamonds. This is because diamonds are graded differently than coloured gemstones, which impacts their value.
Diamonds also have a different density compared to other coloured gemstones. For example, the density of a diamond in 1-carat diamond rings is around 3.5–3.53 g/cm³, while a 1-carat ruby has a higher density of 3.97–4.05 g/cm³. This difference applies to other coloured gemstones, making it difficult to directly compare the carat weight of diamonds and other gemstones or give a combined account in CTTW.
There are two major points to remember:
- Jewellers still give an account of the total carat weight for a piece of coloured gemstone and diamond jewellery but make a point of including the CTTW of diamonds in the description. For instance, this pear emerald and diamond chevron engagement ring shows a total of 1.14 carats. However, the description gives a breakdown of the individual carat sizes of the different types of gemstones.
- The CTTW diamond definition applies to both natural and lab-grown or lab-made diamonds.
Does CTTW Apply to All Diamond Jewellery?
CTTW, or CTW meaning, applies to all diamond jewellery, including rings, earrings, bracelets, etc. For earrings, the CTTW would mean the addition of two earrings in a single pair. To get an accurate CTW for a single earring, you’d have to divide the CTTW by two. For example, this floating diamond inside-out hoop earrings has a CTTW of 0.87 carats, but a single earring in this pair would have a CTTW of 0.43 carats. The same goes for other diamond jewellery.
How Does CTTW Affect the Price of Diamond Jewellery?
The CTTW of a piece of diamond jewellery does not directly affect its price. Two diamond rings can have the same CTTW, but their prices can be totally different.
How? This difference lies in the CTTW of the centre stone and the side or accent stones. For example, a ring with a larger centre stone and fewer accents would cost more than one with the same CTTW but with a smaller centre stone and more accents. This is because large diamonds are rarer and worth significantly more than smaller diamonds of the same quality.
The price difference can also be a result of the diamond quality. If the CTTW of the centre stone and the accent stones for both rings are the same, then the difference may be due to one ring featuring a lower-grade diamond than the other or one ring made with natural diamonds while the other is crafted with lab-grown diamonds (which are 100% identical to natural diamonds, but up to 80% lower-priced.)
The next time you shop for diamond jewellery, make sure you cheque the CTTW to have a clear idea of what you’re purchasing so you’re not caught off guard when your jewellery arrives.
Frequently Asked Questions
1. Does a higher CTTW mean the jewellery is more valuable?
Not necessarily. A higher CTTW does play a role in the value of a piece of jewellery, but there are other factors to consider like the type of stone and stone quality (cut, colour and clarity) which affect the overall value.
2. What does 1.00 CT/TW mean?
1.00 CT/TW means the jewellery piece has a total (combined) diamond weight of 1.00 carat. A ring with one 1-carat diamond or a pair of earrings with many smaller diamonds totaling 1 carat would both be described as 1.00 CT/TW.
3. Does CTTW affect the size of the diamonds?
CTTW (Carat Total Weight) reflects the total weight of diamonds, not their size. Two rings with the same CTTW could have very different-sized diamonds depending on how many diamonds are used.
4. Are lab-grown diamonds measured in CTTW?
The weight of all diamonds, including lab-grown diamonds, is measured in carat size. So, yes, lab-grown diamonds in a piece of jewellery with multiple stones are also measured and described using CTTW.
5. Does CTTW indicate the overall quality of the diamonds?
No, CTTW only refers to the total carat weight of all the diamonds in a piece of jewellery, not their quality. The quality of diamonds is judged by the 4Cs: Cut, Clarity, Colour, and Carat.
