Diamond "Magic Sizes"

The Price Of Diamonds

Diamond price increases almost exponentially with diamond carat weight.

Ok, not really exponentially, but there are huge differences between a 1 carat and a 2 carat diamond.

This can be quite shocking to a first time diamond shopper.

Larger diamonds are simply rare and it follows that they are therefore more highly prized.


Of course sometimes two diamonds of equal carat weight can be sold at completely different prices.

This is because the value will be based not only on size but on three other factors: Clarity, Color, and Cut.

Together with the weight in Carats these make up the four defining  characteristics of diamonds, referred to throughout the diamond trade as the 4 C's.

Magic Sizes

Some weights are referred to as "magic sizes" : half carat, three-quarter carat, and carat. 

There's little difference visually between a 0.99 carat diamond and one that weighs a full carat. Even a 0.92 ct diamond can look pretty much the same to a casual passer-by.

But the price differences between the two will always be much greater than the one percent difference in size. 

They are called "magic sizes" because the price "magically" jumps once it gets to 1 carat and other large fractions, mainly every quarter of a carat. 

Why is this? It comes down to the law of supply and demand. 
 
People love 1 carat diamonds, and it's also easier to refer to diamonds as 1 carat, or half a carat. 

This popularity makes these diamonds with weights of half, three quarter, or one carat sell faster and as a result more rare. 

It is a comfort to know that diamond vendors and wherever you buy diamonds the sales people are prohibited by law from referring to a 0.92 carat diamond as a 1 carat diamond.

And if a dealer refers to a diamond as "About half a carat" they are still required by law to tell you exactly how many hundredths of a carat it weighs.

If they say 47 points, then this is correct, even though they should know better than to confuse customers with diamond jargon.

When they say "47 points" a jeweler is referring to how many hundredths of a carat the diamond weighs.

The correct way to describe a diamond is "zero point forty-seven carats"  as this makes sense to someone who is not familiar with the jewel and diamond trade lingo.

A jeweler may describe the weight of a diamond below one carat by its 'points' alone, though if you don't know what they are talking about make sure you have them clarify.

 

Hiding The Weight In A Poor Cut

Let me explain to you how it is possible for a super ideal cut 0.80 carat round diamond can look the same size as a 1 ct diamond that has been poorly cut. This  doesn’t make sense to a lot of people. 

Take a look at the diagram for this 1.00 carat diamond:,

 It faces-up about the same size as a 0.80 ct super ideal cut diamond

 How can that possibly be? It weighs a whole fifth of a carat more!  

The only thing “comparable” about these two diamonds is that they’re both, well, diamonds.

Let’s look at what we’ve got here:

Upon looking up the diamond grading report for the 1.00 carat “other diamond” that we referenced we can see exactly what is wrong with this diamond.

It’s simply cut too deep.

They were obsiously trying to keep the diamond at one carat.

It's also possible they were trying to do the best they could possibly do with a leftover piece of rough.

It's just as probable it was cut by a beginner who is still getting the hang of the cutting wheel.

The problem here is, well, pretty much everything.

The total depth measurement of 65.7% is simply too deep.

It should be much lower than that.

Round brilliants should not have a depth ratio outside of 59 – 62%.

Diamond cut quality makes a huge difference!

 Now according to the diamond grading report, this diamond measures 5.88 mm – 6.05 mm x 3.92 mm.

The first two measurements are the diameter of the diamond, length & width.

The last measurement is the depth of the diamond, as measured from the top of the table facet, down to the culet of the diamond.

In the diamond business, we tend to talk about the “average outside diameter” of diamonds, because this dictates the size of the “head” or prongs that will be used to set the diamond.

To determine the outside diameter of a diamond, simply add the two outside diameter measurements together, then divide them by two.

Like this:
5.88 + 6.05 = 11.93 / 2 = 5.965 is the average outside diameter for this 1.00 carat round diamond.

Now let’s take a look at the measurements for a 0.806 carat, G-color, VS-1 clarity, super Ideal Cut round diamond. According to the diamond grading report, it measures 5.96 X 6.00 X 3.68 millimeters.

Do the calculation provided above: 5.96 + 6.00 = 11.96 / 2 = 5.98 millimeters.

You still with me?

Thus the 0.80 carat, Signature round diamond, really does face-up around the same size as the 1.00 carat diamond we are comparing it to.

Isn’t that something?

Smaller Diamond. Same Size.

As mentioned in the beginning of this article larger diamonds cost more than smaller diamonds.

There is a price per carat increase that occurs between the 0.89 – 0.90 carat, and 0.99 – 1.00 carat marks. which is the reason why 1.00 carat diamonds are supposed to cost more than 0.80 carat diamonds. But there is another little known factor that contributes to the price of a diamond.

Did you know this little known fact?

Diamond cut quality can affect the value of a diamond by as much as sixty percent. The value of the 0.806 carat, G-color, VS-1 clarity, Signature cut round hearts and arrows diamond is worth more than the 1.00 carat diamond that you’re looking at, simply because it has better proportions, better polish, better symmetry, and incredibly better light performance!

And that difference clearly affects how the diamond looks.  

Look how crisp and clear a super ideal cut diamond looks, in comparison to that other one.

The difference is like night  and day.

Do you see how evenly the reflections of light are distributed throughout this diamond?

Imagine how incredible this diamond will look on someone's finger… This 0.80 carat diamond might be the same relative size as the 1.00 carat diamond that we were looking at, but the two diamonds aren’t even in the same universe when it comes to light performance.

In fact, just about the only thing these two diamonds have in common, is that they have virtually the same average outside diameter.

Want to know a secret?

These two diamonds were probably cut from a piece of diamond rough that was around the same size.

The difference in the resulting carat weight, is because  ideal cut diamonds are cut for light performance, not retention of carat weight.

A good cutter will carefully plan the cutting of every single  round diamond, so that it delivers the highest volume of light return possible.

They want to optimize the proportions of the diamond, to ensure that the diamonds exhibit a virtual balance of brilliance and dispersion.

They’re cut to sparkle, that’s the focus.

And now you know why, a 0.80 ct super ideal cut diamond can face-up larger than a poorly cut 1 ct. diamond.

And that’s just crazy. Isn’t it?