Diamond Shapes

Round Brilliant

The Round Brilliant cut diamond is by far the most popular diamond shape in the New Zealand market.

Round Brilliants are the most optically efficient of all diamond shapes due to the shape and defined proportions that yield the most brilliance.
In 1919 Marcel Tolkowsky defined the parameters which formed the basis of the Ideal or Excellent cut we have today.
Although there are no internationally recognised make parameters for round brilliants that have been accepted throughout the diamond and jewellery industry, the GIA, HRD and other diamond laboratories all have their own classifications of make.
diamonds.co.nz uses the Gemlab make grading parameters for round brilliants only.

Diagram Round diamond facets

Princess

The Princess cut has become a very popular cut all over the world and now ranks as the second most popular diamond cut in the New Zealand market.

The Princess was developed in the 1970s as the Quadrillion.
Preferably square in shape, with corners on, the Princess can also be rectangular it is a modified Brilliant cut, usually with a minimum of 57 facets (21 Crown Facets, 32 Pavilion Facets and 4 Girdle Facets).
Well-made Princess cut diamonds show very good brilliance. Always try to buy Princess with some crown height as a lot of Princess can be very flat in the crown and have very large tables.

Cushion

The Cushion cut is a square or rectangular diamond cut with rounded corners, somewhat resembling a pillow shape, hence the name.

It is a variation on the brilliant cut and cushions can come in different faceting patterns.
They tend to have good brilliance, but slightly less brilliance than round diamonds.
They usually have 58 facets, but some have more because there are a number of branded cushion cuts on the market
A popular shape in New Zealand due to its antique appearance when mounted and a good shape for halo type designs.

Pear

Well cut Pear shapes are beautiful looking diamonds. Demand in New Zealand is limited but has increased recently, especially in larger sizes. Pears make excellent ring and pendant stones and can visually appear much larger than their actual weight.

Pears should have similar proportions to round diamonds, especially in table %, crown height and pavilion depth percentages.
Symmetry is very important in Pears.
Length to width ratio should be around 1.5:1.0
Very suitable as ring and pendant diamonds. Also used as shoulder stones in matched pairs.

Marquise

The Marquise cut is an elongated boat-shaped cut with curbing sides and pointed ends. The Marquise is believed to be named after the Marquise de Pompadour, a mistress of King Louis XV of France. Marquise are gaining in popularity in the New Zealand market.

Developed in France in the 18th Century.
Length to width ratio is ideally 2:1 but personal preference can see demand for longer thinner stones or shorter wider stones.
Symmetry is very important and Marquise can tend to display the "bow-tie" effect in the middle of the stone if they have been cut too deep.

Emerald

The Emerald cut is popular in New Zealand due to it being a classic diamond cut, rectangular or square step cut with diagonally cut corners.

Emerald cuts are the most popular of the rectangular shapes, although because of the popularity of Princess cuts, square emeralds are in demand.
Length to width ratios should be around 1.5:1.0, but again personal preference can prevail.
In the New Zealand market, VS and SI clarities are the most popular, as lower clarities in Emerald cuts are very visible due to the step cut.
Emerald cut diamonds need to be cleaned regularly to ensure their best appearance.

Radiant

The Radiant cut is the proprietary name for a rectangular or square brilliant cut with 70 facets. The Radiant has gained in popularity in the New Zealand market due to its combination of the classic emerald shape and the brilliance of the round brilliant.

The Radiant cut was developed by Henry Grossbard in 1977.
Normally rectangular in shape but also popular in square.
Be wary of Radiants that are cut too deep and have very thick girdles.

Oval

The Oval is a brilliant cut diamond that can display brilliance very similar to a round stone. Ovals are quite popular in the New Zealand market, especially in larger sizes.

Oval as with Pears should have similar proportions as a round diamond, especially in table %, crown height % and pavilion depth %.
Length to width ratios should be around 1.5:1 but personal preference can prevail.
Symmetry is important and the corners (or shoulders) should be nicely rounded to give the classic oval shape.

Heart

The Heart shape is the most romantic of the diamond shapes. This shape is one of the most difficult for diamond cutters to cut due to its complex shape. Basically, it is a Pear shape with a cleft in the rounded end.