Last Updated on 01/01/2024 by Wit Sudjaiampun

1 Carat Diamond Ring Price and How to Buy


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“What is the price of a 1-carat diamond?” Is the question you might be wondering right now, same as many of us who are looking for the perfect diamond for your engagement ring.

Generally, the price of a 1 carat diamond ranges from THB 80,000-600,000. That depends on several factors such as color, clarity, cut, etc.

If you are a consumer who does not regularly buy diamonds, you might be wondering why the diamonds price in a 1 carat diamond varies a lot?

We will find the answer together in this article. I will be focusing on round cut diamonds only as it is the most popular diamond cut.

Read more: 12 fancy cut diamonds and the secret techniques to buy them!

diamond's carat weight

Basic Knowledge: Diamond Carat

For measuring the weight of every single diamond on earth, there are only 2 fixed-rules.

  • 1. The weight of the diamond is always measured in carats.
    Example: If a diamond of 0.5 carat (5 points) has the price of THB 90,000 per carat, that means that diamond will have a price of THB 90,000 * 0.5 carat = THB 45,000 per diamond.
  • 2. The price of diamond per carat will increase as it reaches a higher grade
    Similar to buying a European car, the more options you add – the price is brought up, almost to the point where you could buy another Japanese car.
    So the price of the diamond will increase exponentially with the weight of the carat. That is because the increased price is from the increased weight of the diamond itself plus the increased price per carat.

Interesting fact: 1 diamond point = 0.01 carat


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Things To Consider: Diamond Grades

The reason I emphasize diamond grades is that you might misunderstand that a diamond’s price per carat will increase with its weight. That is not always true because diamond is a product that is bought and sold by emotions above reasoning.

Example: Even though a 0.99 carat diamond will have a 1% higher price than the same quality 0.98 carat diamond. But if it is a 1 carat diamond, its price will be 5-15% higher than a 0.99 carat diamond of the same quality.

Why is it like that?

It could come from the proud feeling you get from being able to say that your diamond is fully 1 carat. If properly analyzed, the reason why people prefer 1 carat diamond is because of psychology and demand.

And this is the reason why there are many lower grade diamonds mixed in the market.

1 carat diamond ring

Read more: How to easily and precisely measure ring sizes at home

How Does The “Cut” Affect The Diamond’s Price?

From what I have said earlier, a diamond with a weight of 1 carat might have a higher price than a diamond of 0.99 carat by 5-15% (it also depends on the quality of each diamond).

If you are following my thoughts, you might be wondering “Then will the jeweler who cuts the diamond down to 0.99 carat get fired?”

In reality, if a 0.99 carat diamond has a better cut than a 1 carat diamond, its price might be lower by only 3-10% because the consumer still values the full carat more.

This is one of the techniques that the giants of this industry know – a diamond should be cut within the grade of 1 carat.

A common technique is to take a diamond which is suited for a 0.75-0.85 carat cut (because it will have the best sparkle) and cut it to weigh more than 0.96 (rare) so they can sell it at the price of 1 carat whilst whole-heartedly knowing that the proportions might not be appropriate for the diamond.

This is the reason why I do not recommend you to buy a diamond which has been set into the ring. You will not be able to measure the weight of the diamond itself. This is a trick of how some diamond stores can camouflage their cheap diamonds and sell them.

Read more: Buying engagement rings from department stores, online stores or private jewelers

Below is the example pricing of diamonds (USD) which increases depending on the carats. You will notice that the more carats a diamond has the more exponentially its prices will grow.

Diamond selling price

Above Diamond

Standard Price Table of 1 Carat Diamonds (Rapaport Price List)

In pricing diamonds, we can categorize them into two groups – group one that refers to the standard diamond price and group two prices their diamonds without referring to the standard diamond price. I will talk about group one.

The table below is showing the standard price of a 1 carat diamond which was updated on 27/08/20. The currency has been converted from US dollars to Thai baht.

The data on the horizontal line is “Clarity” or the clearness of the diamond. The data on the vertical line is “Color” or how pure the color of a diamond is.

D (100)803,000624,200503,700427,100343,100
E (99)613,200532,900456,300390,600317,600
F (98)543,900485,500419,800365,000299,300
G (97)419,800397,900368,700324,900277,400
H (96)343,100324,900303,000281,100255,500
I (95)284,700270,100255,500237,300211,700
J (94)233,600219,000204,400189,800171,600

Browse: our selection of certified diamonds

What is a Rapaport Price List?

The standard diamond price table (Rapaport Price List) originated from Mr.Martin Rapaport who is a jeweler from Antwerp, Belgium.

In 1975 he started selling loose diamonds in New York, some of them have been cut and some of them have not been cut. In 1978 he combined them into a standard price table for ease of selling, and so that became the standard diamond price or the “Rapaport Price List” which is popular till this day.

Rapaport Price List (or shortly, Rap List) is updated every Friday but normally the price does not change much or it will change once in a few months.

Rap List is used as a standard in pricing all loose diamonds that are sold in the Clarity Grade of SI3 or more, and the K color or higher (even though the Rap List will indicate pricing for lower grades, it is not commonly used).

Learn more: 4C’s of Diamonds

Discount & Premium

Buying diamonds is both a science and art form because in the Rap List there might be some diamonds that have a discounted rate whilst some diamonds might have a premium rate.

Many factors contribute to the pricing of a diamond stone, other than the weight (Carat) and the color, there is also the cut, the flaws (Inclusion) and the fluorescence that has to be considered.

That is why the pricing of diamonds can be a hard concept to grasp for general consumers who are not inside this industry. That is why you should find a friend who is in the diamond business, so you will be able to ask them for advice.

Read more: 4 Tips in Choosing ‘Women’s Diamond Rings’ That Will Make You Look Elegant and Beautiful!


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Sweet Spot of Value

Back to the pricing of diamonds in the Rap List. I want you to take a look at how the 1 carat diamond is priced in the table.

Do you notice something strange?

Yes, that is correct. The prices in the Rap List have no consistency!

Example: If you consider the price of a 1 carat diamond, you will find that between the D / VVS2 and E / VVS2 has a price difference of a whopping 87,000 but if you lower the color grade by 1 to F / VVS2 the price difference with the E / VVS is only at THB 26,000.

That means that if you buy a 1 carat diamond of the E / VVS 2 grade, you will be able to save much more than buying a D / VVS2 1 carat diamond.

Why is the price difference so significant?

Personally, I cannot give you a conclusive answer, as I have said before – diamond is a product that is bought with more emotions than reasoning. The reason for the popularity of D Color diamonds is fully psychological.

In the example above, you will clearly see that buying a 1 carat diamond of D / VVS2 grade is not as worth it as buying an E / VVS2 diamond because of the huge price difference.

That is how we can conclude that when buying a diamond you do not always need to choose the highest specifications. Unless you have an abundance in budget and a special fondness to buy it.

Read more: What Are Triple Excellent Diamonds? Let’s Get to Know Them!


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Discover the Price of a 1 Carat Diamond Right Now!

You can click on the link below to view the price of our selected 1 carat diamonds today.

Price of 1 Carat Diamonds

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