Decoding the 5th C of a Diamond – Cost (Diamond Cost)

I hear you! There is already so much information about diamonds and diamond cost, and yet I have heard from many that they find diamond pricing to be one big maze. Understanding diamond costing gets overwhelming for them and hence they avoid buying it altogether. That’s why I want to write about it again, to simplify the intimidating and sparkling world of diamonds and their cost.  

Read on; there might be a perspective to 4C’s beyond the stuff you have read before and you don’t wanna feel duped while purchasing a diamond. We will help you decode the cost of diamonds

Undeniably, while the newer and younger generation loves to travel and gather experiences more, there is still a bunch who love diamonds to the point that they often cringe! 

Why understanding 4C’s is important? 

Have you often wondered? 

  • One diamond looks bigger than the other even though the carat is the same 
  • Apple to apple comparison, one diamond shines more than the other
  • Again, apple to apple comparison, yet one cost more than the other

Of course, you may beg to differ if you are an industry expert. Still, in layman’s terms, for someone who wants to buy for ornamental purposes, this blog will help you understand the inner workings of diamonds, 4C’s, and the relationship of 4C’s with the 5th C – Cost.

Overview (literally!) of 4’C – only to get it out of the way 

In fact, there is a RIGHT order to this, 

Cut: It determines how well a diamond reflects and refracts light, impacting its brilliance and sparkle.

As per the grading system, there are 4 types of cuts. In the order of best to poorest, as the names are self-explanatory:

  • Excellent 
  • Very Good 
  • Good
  • Poor 

Colour: It refers to the presence of any colour in a diamond, and the grading helps determine its rarity and value.

From D to Z, the diamond’s colour is graded using a letter grading scale, with D being the most colourless and Z being the least colourless.

  • D, E, and F being excellent, a colourless diamond
  • G, H, I, near colourless
  • K-Z, colour gradation gets darker from the naked eye 

Clarity: Since diamonds are found in nature and are full of earthy materials, diamonds come with internal and external flaws or inclusions. 

Clarity basically refers to the flaws found or not in a diamond.

  • FL, Flawless – Barely used commercially as the pricing is high.
  • IF, Internally Flawless – Used commercially, but again pricing is important.
  • VVS, Very Very Small Flaws – A preferred choice for many, if a diamond is big and can’t be seen with the naked eye, generally speaking, they are black/ brown tiny dots size inclusion.
  • VS, Very Small Flaws – Popular choice, can be seen with the naked eye if the diamond is big in size – broadly speaking, they are tiny dot size to a slightly bigger dot.
  • SI, Small Inclusion – Commercially popular, can be spotted easily with the naked eye, bigger than dots.  
  • I – Inclusion – Commercially popular, can be spotted easily with the naked eye. Easily visible spread out areas of black and brown   

Carat Weight: It measures the weight of a diamond

  • The carat weight measures the weight of a diamond rather than its physical size. 
  • Carat weight is distinct from the actual size of the diamond. 
  • For instance, a one-carat diamond weighs approximately 0.2 grams. 
  • Carat weight is a significant factor, however, in an apple-to-apple comparison from a weight standpoint, it is considered the least influential of the 4 Cs of diamonds. 
  • For eg, if two stones are 1 ct each, the other factors determine the cost of the diamond.
  • Two diamonds with the same carat weight but different shapes vary significantly in size.

How do the 4C’s work together? 

4C’s of the diamond determine the 2 most important things for a buyer: 

  • How the diamond shines and looks 
  • Price of the diamond

While the combination of 4C’s play a critical role in the pricing of the diamond to arrive at the 5th C, Cost, several other significant factors play a part in arriving at the cost, such as Rapaport, shapes, flourscenes, demand and supply.

Let’s understand each one by one:  

Heard of Rapaport before? 

You are at the right place. We will tell you about that very connection between diamonds and Rapaport. 

The Rapaport Report, named after Martin Rapaport, the founder of the Rapaport Group, is a leading diamond trading network and provider of diamond market information.

Mr Rapaport is considered to be one of the most authoritative people in the diamond industry, influencing the global market regarding a uniform pricing structure, be it India, the United States, Korea or Japan. 

What is Rapaport Diamond Report?

Rapaport Diamond Report, informally known as the Rap List or Rap Sheet, is a price list or pricing system for diamonds. 

  • The Rapaport Diamond Report is a benchmark for diamond prices based on carat weight, colour, clarity, and cut factors.
  • It is widely used as a reference guide by diamond dealers, retailers, and industry professionals to determine the market value of diamonds. 

How is Rap Sheet relevant to you as a BUYER? 

Rapaport Report Sample

You need to know about the Rap sheet, which is relevant to you, especially if you are a frequent/first-time buyer of larger diamonds.  

Jewellery salespeople often use the term ‘Rap Sheet’ in retail as a marketing pitch. 

Remember, the Rapaport report is a theoretical system of base guidelines to ascertain diamond prices. Rapaport report indicates diamond prices based on high asking prices, quality, and ideally cut diamonds. 

Suppose a jeweler is showing you the sheet and suggesting a percentage discount. In that case, you should double-check pricing from other places before purchasing. 

  • The rap sheet is updated weekly Thursdays at 11:59 pm EST. 
  • Diamond cost is far more complex than just a rap sheet; factors such as demand and supply, availability of stock, shape, and fluorescence also play a huge role before deciding the diamond prices. 
  • Bulk pricing of diamonds by diamond traders is determined from Rap. 

Usually, larger stone prices get impacted weekly after the release of the Rap sheet. 

How does the SHAPE impact price of the diamond? 

In the context of diamonds, a cut refers to how the diamond’s facets are arranged, while shapes, on the other hand, refer to the overall outline, form, or silhouette of the diamond. 

Indeed round is the most popular and common shape. 

In addition to round, some other shapes are square (also known as princess cut), oval, radiant, cushion, asschers, hearts etc. In industry jargon, non-round shapes are called ‘Fancy Shape Diamonds.’ 

  • Rounds fetch the most price as compared to other shapes. The reason is that the round shape cut can scientifically refract the light the most, thus causing the diamond to shine or sparkle more than other shapes. 
  • The number of facets in a round is more than other shapes as well. 
  • As mentioned earlier, round diamonds will fetch a higher price than other shapes in an apple-to-apple comparison. 

Personally, I have a weak spot for fancy shapes. However, the round is a classic choice for most. Choose any, diamond cost will depend on a combination of many factors and not shape alone.  

How does the FLOURSCENCE impact the diamond cost? 

Basically, the coloured luminous glow (mostly blue) is visible when kept the stone under UV light. 

  • Diamonds that have strong fluorescence end up looking milky or lifeless therefore are cheaper than others
  • Diamonds with none-to-faint fluorescence may be a tad bit more expensive than the other alternative 

Why opt for Certificates?

GIA diamond Report SampleThe diamond certificates issued by reputable third-party organizations provide a detailed analysis of the diamond’s 4Cs and other important attributes. 

These certificates authenticate the diamond’s quality, giving buyers confidence in their purchase and facilitating transparency in the diamond cost adding credibility to the diamond industry and the seller.

Certificates don’t directly mention the 5th C, i.e., the diamond cost. Most jewellers, traders and industry professionals map the certificate details on the Rapaport report and factor in market conditions to arrive at the selling cost of the diamond. 

Generally, the larger diamonds (anything above 0.2ct) are sent for certification as the cost is high. Of course, there are 

  • Gemological Institute of America (GIA): Known to be the most respected and popular third-party laboratory worldwide 
  • American Gem Society (AGS)  
  • International Gemological Institute (IGI)  


Did you know Emerald is referred to as cut in diamonds even though it is a shape?  

The emerald cut is named after the gemstone emerald because it was initially developed and commonly used for emerald gemstones. 

Over time, its unique rectangular shape with step-cut facets became popular. 

It also began to be applied to diamonds, retaining the name “emerald cut” even when used with diamonds.

Summing up

Diamond cost can vary from jeweller to jeweller. Well-known pricing factors (4C’s) and others (mentioned above) contribute to arriving at diamond pricing.

Despite bringing some uniformity by Rapaport Diamond Report, there is a possibility in an apple-to-apple comparison that the diamond pricing differs by up to 5% from one trader/jeweller to another. 

Hope this helped you decode and recode the cost of diamonds to make a well-informed purchase.

Still confused or unsure? Stay calm, and write to us at, we will try to help you find answers to your questions.

Until then, may the diamond shine on you!

You may also want to read about the lab-grown diamond gifted by Mr. Modi, India’s prime minister to Jill Biden, First Lady of the United States of America.

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