Charles Rose

Diamonds never fail to delight and dazzle with their prismatic brilliance and remain a popular gift of choice to express eternal love and commitment. Purchasing diamond jewellery is a personal journey because there are many considerations including style, budget and preference. However, additional key factors must be considered before selecting the perfect diamond for you.

The Gemological Institute of America (GIA) established the 4Cs – a universal standard grading system – to assess the qualities that determine a diamond’s value. However, there are many confusing technical terms used by jewellers that most people, particularly first-time buyers, do not fully understand. To make your diamond jewellery purchases easier, Charles Rose have created helpful educational guides to the 4Cs of diamond cut, diamond colour, diamond clarity and diamond carat weight. The diamantaires at Charles Rose believe that the more you understand about diamond quality, the more confident you will be when choosing your perfect diamond.

Understanding Carat Weight

The term carat is often mistaken as referring to diamond size. However, a carat actually refers to a diamond or gemstone's weight. A metric carat is the standard unit of measurement for diamond weight. A 1-carat diamond weight equals 200 milligrams (0.200 grams). Diamonds less than a carat can also be measured in point increments up to 99 points; one full carat equals 100 points. A diamond equal to or heavier than 1 carat is expressed in carats alone. So, a 1.75-carat diamond weight refers to a 1 carat, 75-point stone. Carat weight is the most objective of the 4Cs to define because it is measured using a highly accurate digital scale.

Debunking the Carat Myth: Why Cut Matters

Another common mistake people make when purchasing diamonds is believing that a higher carat weight equates to more sparkle. A diamond cut can significantly influence the appearance of a diamond and is the most crucial factor determining a stone’s brilliance and sparkle, not the diamond size or weight.

In fact, poor cut 1.5-carat diamonds often lack sparkle and appear duller and smaller than 1-carat weight ‘Ideal’ or ‘Excellent’ cut diamonds precisely proportioned and polished with beautiful symmetry. High-quality cut diamonds can also appear larger while offering maximum sparkle and brilliance because the stone’s weight is not hidden by the setting. Instead, the weight is maintained in the visible portion of the diamond.

Understanding Diamond Carat Size

Although diamond carat weight and diamond size are related, they are not the same. Diamond size refers to the stone’s physical length and width dimensions measured in millimetres. Therefore, two stones can be the same carat weight but can be different sizes because their dimensions differ. Conversely, stones can have the same diameter or depth but differ in carat weights.

Shape also impacts a gem’s appearance. Diamond shape can make two stones with the same carat weight appear different, as elongated diamond shapes like rectangles and ovals give the illusion of being larger than square or round shapes. This is one of many factors, in addition to diamond colour, diamond clarity and diamond cut , to consider before purchasing diamond jewellery – all affect whether a gemstone appears bigger or smaller to the naked eye than its actual carat weight. What is the best diamond shape? Well, that depends on your personal preference. It is advised that you consider all the 4Cs before deciding what the best shape is for you.

Diamond Carat Size Chart

Diamond carat size chart

From top to bottom the carat sizes go as follow:
0.57ct, 1.01ct, 1.57ct, 2.22ct, 2.90ct

Utilising Diamond Carat Weight Chart

Diamonds are valued on a per carat basis, so the accurate measurement of diamond carat weight is important because it helps establish a gemstone’s value. Diamond carat price is calculated by multiplying the carat weight by the price per carat. However, large natural diamonds command premium prices because of their rarity in nature. Consequently, the price per carat rapidly increases as the diamond carat weight increases. Notably, two diamonds of equal carat weight can be valued and priced very differently depending on the diamond’s other qualities – cut, colour and clarity.

Additionally, carat weight should not be confused with total carat weight when referring to popular diamond and coloured gemstone jewellery designs featuring multiple accent diamonds. While carat weight refers to the weight of a single diamond, total carat weight measures the weight of all diamonds combined in multi-stone jewellery. For example, a solitaire engagement ring with a single brilliant diamond weighing 1-carat will be more expensive than a three-stone trilogy ring with a 1-carat total diamond weight, assuming they have equivalent diamond cut, colour and clarity qualities.

Diamond Carat Weight Chart

The following diamond carat weight chart is an ideal way to help you visualise the physical size of a diamond with respect to a corresponding weight, showcasing the relationship of carat weight vs size. It is a useful guide for all diamond jewellery buyers as it illustrates how diamond carat weights and shapes appear when viewed from the top.


Diamond Carat Weight Chart


Factors to Consider When Buying Diamond Jewellery

As our diamond carat weight guide highlights, when buying a diamond, higher carat weight and bigger size are not necessarily better. Scintillating shimmer and breathtaking brilliance will always eclipse diamond carat weight.

Charles Rose diamantaires recommend that you use our helpful 4Cs guides to help you compare and evaluate all four diamond qualities before making your final decision. Just like every diamond, you are unique. So, it is best to focus on the diamond quality factors that most appeal to you and meet your personal preferences and budget. For more information on the 4Cs, see our ultimate guides to diamond cut, diamond colour and diamond clarity.

Our expert diamond consultants are also available to discuss the finer intricacies of your diamond selection. Contact Charles Rose today and book an appointment at one of our Melbourne or Geelong showrooms and discover the difference of our ready-made and bespoke fine diamond and exquisite gemstone jewellery.

marcus rose


Authored by Marcus Rose, third-generation custodian of Charles Rose Jewellers' legacy since 1995. Upholding the founders' values of superior quality and unparalleled beauty, Marcus ensures every meticulously crafted piece tells its own unique, enchanting story.



Hear what some of our customers had to say about the quality and value of our diamonds:

"Gorgeous diamonds for incredible value. The staff whom we have dealt with for my engagement ring and our wedding rings went over and above to ensure that we are 100% satisfied with our purchase, whilst being incredibly patient during the process. We found that The Charles Rose diamonds and jewellery are exquisite & we will not be going anywhere else!” - Samantha Hommelhoff

“The customer service is great. There is no pressure and the staff are really helpful. My wife loves diamonds and this is the place” - John Atherton