No matter the technological advances or what jewelry trends come and go, our passion for diamonds remains unbreakable. Diamonds are the most coveted gemstone. As a luxury item, however, they also come with a luxury price tag.
Several factors influence the price of a diamond. Industry standards are determined by what is known as the 4 Cs
This applies to loose diamonds. For cut diamonds and diamonds set in pieces of jewelry, other factors are playing into the price you pay for the item. For example, the price of a diamond engagement ring will take into account
- the size of the diamond
- the quality of the diamond
- the precious metal of the ring band and the design
Sometimes the brand, retailer, or designer name will be accounted for too.
There is an important addition to the 4 Cs – making it obvious, the 5 Cs. The 5th C is certification. In the USA diamonds are certified by the GIA – the Gemologist Institute of America. The GIA certificate is a full scientific and unbiased assessment of a diamond's 4 Cs.
For most of us, the thing that most attracts us to a particular diamond is its shape. The shape is chosen by the cutter as the best form to produce the most brilliant diamond from the uncut stone.
The Diamond Cut
When diamonds are mined, they look nothing like a product that sits so stunningly in a piece of jewelry. It is down to the skilled artistry of a diamond cutter to produce a shape that reflects the stone’s true beauty.
The cut/shape the cutter produces is designed to highlight the best way the stone’s facets (flat surfaces) interact with light to produce those visual effects that attract us so much: brightness, scintillation, and fire.
- Brightness - This is the way white light is reflected from the diamond both internally and externally
- Scintillation – this refers to the sparkle produced by a diamond and the planes of dark and light areas caused by internal reflections of the facets
- Fire - this is how white light within the diamond scatters into prisms
The cutter will cut, shave and shape the diamond to produce a stone with the proportions, symmetry, and polish to achieve the magnificent light and sparkle only a diamond can produce. The workmanship of the cutter will be reflected in the diamond’s final beauty and value.
The Different Diamond Shapes
A diamond’s shape is its external structure. Along with the 4 Cs, shape affects the value of a cut diamond. And, when it comes to pricing and value, all is not equal. Generally, the most expensive shape is also the most common, the round diamond, more correctly known as the round brilliant. This is because it uses less of the rough diamond. The shapes that use more of the rough diamond cost less per carat.
Here is the full list of diamond shapes:
- Princess cut
- Radiant cut
- Emerald cut
- Cushion cut
- Round cut
- Pear cut (aka teardrop cut)
- Marquise cut
- Asscher cut
- Ashoka cut
- Trillion Cut
- Oval cut
- Heart cut
There may be other fancy-shaped diamonds but these will be bespoke – someone for example might request a triangle or pyramid.
It often comes as a surprise to diamond buyers that some shapes cost more than others and that the fancy diamond shapes have a lower per carat price than round diamonds.
The Pricing Factor
On average you can expect to pay 20 to 40 percent more for a round cut diamond than a fancy-shaped diamond of comparable weight and qualities.
This seems at odds with what has been said about the 4 Cs. Surely, pricing is based on the combined grade of cut, color, clarity, and carat weight? How does shape affect this?
What hasn’t been mentioned as yet is the loss factor. During the cutting and polishing process, a percentage of the rough diamond is lost and this is accounted for in the price. The loss is an average of 20 to 60 percent of the original rough diamond.
Typically, with a round brilliant cut diamond, 60 percent of the rough diamond is removed compared to a princess cut, where 20 percent is lost.
Other than maybe being able to be used as pavé diamonds (diamond chippings), there is no use for the “lost” parts of the rough stone.
Despite the loss factor, round cut diamonds are the most popular and this shape accounts for ~75 percent of all diamonds sold worldwide.
The Prices for Each Diamond Shape
It is not possible to categorically state a diamond price because retailers will have their own valuation systems and there are also worldwide market forces to take into account. However, some guidance can be given.
We have used prices – at the time of writing - for one-carat diamonds (or nearest to one carat) as quoted by the James Allen website – one of the country’s most respected diamond retailers also known for their reasonable prices. We have also compared diamonds of similar cut quality (ideal), color (J), and clarity (SI1). All diamonds viewed also have a GIA certificate.
Please note, the prices quoted are very similar to those listed by another reputable seller – Blue Nile.
Round Cut Diamond
The most popular and the most expensive diamond shape. Popularity also plays its part in pricing. The round shape is, by far, the most popular choice for diamond engagement rings so market demand drives the price up.
Price for a 1-carat solitaire round diamond - $3,390
This is the second most popular diamond shape. The shape is an inverted pyramid with a square face. This shape has one of the most economical cuts in terms of diamond loss. Up to 80 percent of the original stone is used.
Price for a 1-carat princess cut diamond - $2,030
With its rounded-off corners to make its basic square shape look like a cushion, cushion-cut diamonds can have a remarkable amount of sparkle and fire. Beyond this basic shape, there are various types of fancy cut patterns. The cushion cut is a popular choice for use in a halo setting.
Price for a 1-carat cushion-cut diamond - $2,050
This shape is elongated and features step cuts to provide a large “table” surface. This shape is liked because it gives the illusion of being larger than other fancy cut diamonds of similar carat size.
Price for a 1-carat emerald-cut diamond - $2,250
Another cut with an elongated shape gives the illusion of greater size. The oval cut is durable and the shape is impressive.
Price for a 1-carat oval-cut Diamond - $2,440
Radiant Cut Diamond
A cut that only came onto the market in 1970 when it was first produced by Henry Grossbard, the aim is to maximize the size and brilliance of the stone. This is another shape designed to appear larger thanks to its large number of facets and it is also a durable shape.
Price for a 1-carat radiant cut diamond - $2,250
Asscher Cut Diamond
This is a step-cut diamond with a square shape but similar to the emerald cut except it has 58 facets. The cut is designed to showcase the stone’s luster and clarity.
Price for a 1-carat Asscher cut diamond - $2,790
Cut to resemble the lips of Marchioness Madame de Pompadour, a favorite mistress of French King Louis XV, this design dates back to the 18th century, gaining the name marquise over time. This is one of the fancy shape diamonds where the design makes it difficult to determine the cut quality.
Price for a 1-carat marquise-cut diamond - $2,480
Heart Shape Diamond
A modified version of the brilliant round cut, the best heart-shaped diamonds have optimal symmetry. Because they use more of the rough stone, heart diamonds are cheaper than brilliant round diamonds.
Price of a 1-carat heart-shape diamond - $2,280
Pear Shape Diamond
The important thing about the pear shape is that it has the right proportions. It should end in a point and this shape is liked for engagement rings and eternity rings because when set and worn on a finger, the point should point to the wearer’s heart.
Price of a 1-carat pear shape diamond - $2,270
The Most Affordable Diamond Shapes
We have already established the shape that is the most expensive per carat is the round brilliant cut. This means that if you have your heart set on a round brilliant, you may have to sacrifice size/carat weight for your budget.
You can see from the figures above that a round brilliant is going to cost at least $1,000 more than an equivalent fancy shape of 1-carat.
Although it is still quite subjective, it is the radiant cut that is probably the most affordable among the most popular fancy shapes.
Any of the fancy shape diamonds offer good value for money per carat against the round brilliant - in order the Asscher, emerald, radiant, cushion, and princess cuts.
This is if the size is your most important factor when choosing a diamond - probably something of most interest when you are looking for an impressive-looking center stone.
Simply though, it is impossible to do a direct comparison as every diamond is different. When choosing a diamond or a piece of diamond jewelry, take all 4 Cs into account.
Learn a little about each of the 4Cs so you can examine the stone/carefully. It is helpful if you can see for yourself if a stone is eye clean or there are inclusions.
Always buy from a reputable dealer or jeweler and never buy a diamond without a GIA certificate.