Shape

Round brilliant cut

The round brilliant cut is the the most popular cut and accounts for more than three quarters of all diamonds sold today.
Based on Marcel Tolkowsky formula which has only been slightly modified since 1919, it is the only cut to have perfect proportions and angles defined to produce a maximum return of light. 

Princess Cut

The princess cut is the second most popular cut shape for diamonds, next to a round brilliant. Princess cut diamonds have 49 to 78 facets, but normally closer to 78 for more fire and brilliants. The princess cut is also referred to as a square modified brilliant, but while displaying the same degree of light reflection, the faceting style is very different from that of a round brilliant. Princess cut diamonds work out slightly less in cost than round brilliant cut diamonds because when cutting a rough diamond into a princess cut it loses about 20% of the weight as opposed to 50% of a round brilliant cut.

Emerald Cut

Emerald cut diamonds are also known as step cut diamonds. Although they have less sparkle than a round brilliant, they are considered to have a more elegant look not seen in other cuts. The quality of the diamond is more important with this particular cut. Inclusions and lower colours are more noticeable in an emerald cut diamond.

Royal Asscher Cut

Developed by Joseph Asscher in 1902, the Asscher cut became the first signature cut to be patented. It was Joseph Asschers company that was commissioned in 1908 by the British Royal Family to cut the largest diamond in history, 3.105 carat Cullinan diamond.
Asscher cut diamonds originally had 58 facets until it was modified with 74 in 2001 by Edward and Joop Asscher for more brilliants and shine.
In 1980 the Asscher company was granted a Royal prefix by Her Majesty Queen Juliana of Holland for playing such an important role in the diamond industry, and the Asscher Diamond Company became Royal Asscher.

Cushion cut

Also known as candlelight diamonds, they range from square to rectangular.
They have a romantic look with there rounded corners and larger facets which give them a soft pillow shape, hence the name cushion.

Radiant Cut

The radiant cut has the fire and brilliants of a princess cut and the sophistication of an emerald cut. Radiant cuts have 70 facets and can vary in their degree of rectangularity. They are very popular for fancy coloured diamonds as their shape intensify the colour.

Marquise

Legend has it that this particular cut earned its name from Louis the XIV (Frances sun king) who wanted a diamond cut so brilliant to match the smile of the Marquise of Pompadour. The marquise cut has 56 facets, and with its elongated shape it has the appearance of being larger than other cut diamonds of the same weight.

Pear Shape

The pear shape is considered one of the most romantic cuts as it has the look of a sparkling tear drop. With 58 facets, its a combination of an oval and marquise cut. Although the pear shape diamonds are beautiful in solitaire engagement rings they seem to be more popular in pendants, earrings and as side stones for a different shape larger center stone.

Oval shape

Created by Lazare Kaplan in the early 1960s, the oval shape diamond has 56 to 58 facets, almost the same brilliants as that of a round diamond but appears larger with its elongated shape.

Heart Shape

Heart shape diamonds are modified brilliant cuts. With there intense sparkle they are one of the most popular cuts for fancy coloured diamonds and are without question the most romantic.