Summary in a few lines:

Diamond weight unit is measured by carat (not to confuse with gold’s karat), carat is 0.2 of a gram, which means that a gram of diamond is equivalent of 5 carats.

Don’t let the 0.2 of a gram make you think it’s so tiny, here is a 1 carat diamond on James Allen, and if you’re a fan of Blue Nile images, here is a 1 carat diamond there.

Probably you noticed the price of a 1 carat diamond, but since the gram is 5 carat, don’t think it will be just 5 times a 1 carat diamond, It might reach 10x! Let’s see why…

Diamond Weight <> Price Correlation

Now that we are clear on the fact that diamonds aren’t sold by the gram, it should be noted that the weight measurement unit for diamonds is the Carat. But how can one actually estimate the price of a gram?

In order to get there, we need to know how much carat is in a gram of diamond. And if you don’t already know that, your mind will be absolutely blown! Let’s put a pin on that for now and talk carats, shall we?

For instance, check out this 1-carat diamond at James Allen’s; priced at $5190 (at the time of writing this), whereas this almost exact one (with double the carat weight) from BlueNile, costs around $17k (which is clearly not double the price of the 1 carat on James Allen’s), any idea why is that?

To clarify, diamond pricing doesn’t work this way, 2 carat diamond price doesn’t necessarily equal double the price of a 1 carat! There’s a whole science behind this; way more than just weight!

One thing you need to know is that multiple factors influence diamond pricing! We’re talking: weight, cut, color, clarity and RARITY! Larger diamonds are much more rare than smaller ones, making them more expensive.

Random note: You can absolutely find a 2-carat cheaper than a 1-carat! But that story is for another day.

How Much Carat is 1 Gram Diamond?

Back to where we left off. Let’s talk mathematics!

A diamond carat is equal to 200 milligrams, and given that gram is worth 1000 milligrams, it means that 1 carat equals 0.2 of a gram and a gram equals 5 carat.

Namely, asking how much 1-gram of a diamond is worth is the same as asking what the price of a 5-carat diamond is!

5-carat diamonds are very rare. To the point that not many people in the diamond industry have ever seen one! To paint you an image, let us tell you that +90% of diamonds you’ve seen in your life are less than 1.5 carats! The same goes for any diamond expert!

How 5 carats diamond looks in real life? The left image is 1 carat, and the right one here is 5 carat, pretty clear how large is it!

Image Source: James Allen

What is Diamond Price per Gram?!

While you probably will never find a 1-gram diamond in your local jewelry store, chances are, you can get an idea or two on its size and price on online stores (which is our preferable way of diamond shopping, actually!)

Being the largest online store with hundreds of thousands of diamonds, James Allen will be our reference for the following price estimation.

Remark: Out of +520k diamonds on James Allen (as of writing this), only ~700 diamonds are 5 carats or more (an approximate ratio of 1:1000).

Because diamond prices vary tremendously; particularly with large diamonds like a 5-carat (1 gram), and there is no one-size-fits-all rule to know how diamonds are priced, we will be covering the mystery of diamond pricing in the following sections!

But as for the 5-carat, it’s safe to say that the cheapest 5-carat (1 gram) diamond is priced at $39600 as you can see here, while the highest-priced 5-carat diamond costs $395600, and no, there are no extra zeros here, $395k! Here’s a screenshot for the record:

No wonder, the diamond industry is insane, and such diamond is exceptionally rare, 5 carat (1 gram), D colored & flawless! 

With that in mind, James Allen is incredibly generous; giving a free ring with the diamond making your money spent absolutely worth it!

To put this into more contest, 1-gram of diamond prices vary a lot, and you can’t limit that to these two diamonds (cheapest and most expensive), feel free to check this pre-set search on James Allen to see the price range before we get into details.

What is Diamond Price Per Carat?

Or in other words, what’s the price of 0.2 gram of a diamond?

You’re most probably at the stage of setting your mind on a budget for the ring. But the question remains, do I have to limit my budget to a particular carat weight? The answer is no, you don’t. We urge you to rather look for a good diamond despite your budget!

However, we sure as hell don’t want you to go through with this without a reference at least, therefore, we managed to get our hands on some of the prices of 1-carat diamonds and estimated that the average of such diamond costs somewhere between $4500 and $7000 (Ideal cut, H or G Color, SI1 or VS2 Clarity), roughly speaking!

If you just change the search above to 2 carat, you will get diamonds ranging between $17k to $29k, this indeed isn’t 2x of 1 carat diamond! It’s almost 3x.

Why the Price of a 2 Carat Diamond isn’t 2x of a 1 Carat?

Diamonds are scarce, and the larger they are, the rarer they get! To demonstrate, James Allen’s has +11,000 diamonds weighing exactly 1 carat, anyhow, they have only 600 diamonds weighing exactly 2 carats! See what we’re getting at here?

We mean, common, you can’t possibly get that in your local store! Not even on most online stores!

To be honest, James Allen and Blue Nile took the online jewelry competition to new levels!

James Allen is currently the largest diamonds online store with +520k choice of diamonds with various carats and cuts! Blue Nile offers 509k as well! Pretty insane!

Back to our topic on hand, does the diamond price only depend on carats? 

Let’s take another quick look at James Allen’s diamond ring setting tool. You can clearly notice that the search limits the options to 1 carat only, and gives us thousands of options ranging between $2000 and $15000.

Yes, a low-quality 1-carat (0.2 of a gram) diamond costs around $2000, whereas a superior 1-carat diamond might cost approximately: $15000 for a brilliant-cut, extremely high clarity, and a gorgeous shape!

The same goes for 2 carats, if you include low quality grades (color & clarity) as well as superior grades, you might be looking at a number as high as +$44000 or as low as $6000! as you see in these two screenshots:

In conclusion, a 2 Carat diamond is not a 2 x 1-carat diamond, it’s actually almost 3x.

Why? As simple as 1 word: Rarity!

What Factors Count into Diamond Pricing?

Diamonds are extremely unique, And like the iris of the eye, you can never find two identical diamonds on earth.

As we’ve already discussed, many factors come into place when it comes to diamonds and so lots of variables sum up the final price of a diamond!

We have quickly mentioned these factors: Carat, Cut, Color, and Clarity. Let’s go a bit deeper:

1- Cut:

Cut is the most important element in any diamond. It’s mainly responsible to make the diamond proportion ideal in order to reflect most of the light that goes through it. This image tells you the whole story behind the Cut:

Diamond Cut Light Reflection

Quick Tip: Always seek an ideal cut (start from there), then look for other factors based on budget (i.e. don’t start by: I have $5k and want 1 carat, let’s see what cut/color I can get)

2- Color:

The moment your heart is set on an ideal-cut, you’re starting to think “Colors”! You’re lost between the colorless and the yellowish. Well, before you decide, you should probably be aware of the Diamond Color Chart that you can see down the article there!

According to GIA standards, diamond colors are scaled from D to Z, with D being the most colorless grade:

Diamond Color Chart with Fancy Colors

Quick tip: In 99% of cases, you will be safe getting an H color diamond.

3- Clarity:

This factor determines how clean the surface of a diamond is, if it has inclusions (flaws) or not, what types is the inclusion, and if the inclusions are visible to the naked eye or not.

And again, we have another chart grading all diamond clarities for you: Diamonds Clarity Chart from I3 to FL.

Quick Tip: SI1 is eye-clean in most cases.


These 3 factors (along with many others like certification labs which assess the diamond, polish, symmetry, etc…) play a huge role in determining the price of a diamond; which’s the reason for the huge gap that we see between the prices of a 1-carat!

To give a clear example: A diamond with an excellent cut, D color, VVS1 clarity price will cost 5 or 6 times more than one with only a good cut, K color, and I1 clarity diamond.


Diamond weight isn’t measured by gram, rather by carat, which is 0.2 of a gram.

1 carat diamond costs somewhere between $4.5k to $7k for recommended grades (Ideal cut, H or G Color, SI1 or VS2 Clarity).

1 Gram of diamond can cost as low as $39.6k, or as high as $347k.

The price of any multiple of a carat (2 carat, 3 carat, gram, etc..) isn’t the multiplier of 1 carat diamond price, for many reasons, but mainly rarity! The larger the diamond, the less available it is.

When you’re searching for your perfect diamond, Carat is the last thing to look for (from the 4Cs). We suggest you consider the other 3Cs first and… the tips below:

  • Always start with the cut. Don’t get below a Ideal cut diamond, even if it was smaller in size. A 0.5 carat ideal diamond might be better than a 1-carat v.good one!
  • Next, head to color and spend your money on what matters. H will be good enough!
  • As for the clarity, get an eye-clean SI1 and you will be just fine.
  • Make sure that your diamond is certified by a well-known lab like GIA (the best certification lab) or AGS, and please don’t think about getting one certified by EGL !

Lastly, we always recommend our readers to shop online for a variety of reasons, and among all online vendors, Blue Nile & James Allen offer the widest collection & best prices online.

Happy diamond shopping!

Find the One James Allen