advt 120x600

advt 120x600

Round Brilliant cut diamond shape is the most popular shape of the diamonds. Round cut diamond is more brilliant than diamonds of any other shape. An ideal cut Round diamond produces excellent sparkle, which is an essence of a diamond ring.

Brilliance of a diamond stone is determined by the way it handles light that enters into it. An ideal cut round diamond can handle light most efficiently and reflect almost all the light that enter into it. This results into great brilliance. Such diamond stone is ideal choice for making a good engagement ring.

Round diamonds are very versatile. They are used in engagement rings, wedding rings and anniversary rings. They are also used in nose pin, stud, earrings, bangles, wedding bands and pendants. Every 3 in 4 diamonds are cut into round shape.

Diamond cutters attempt to cut every diamond into the best proportions to attain balanced return of light (utmost brilliance) and dispersion. Diamond is called brilliant if the cutter cuts it with numerous facets to achieve great brilliance. Each flat polished surface of diamond stone is called a facet.

When crude diamond is cut into a final shape, it results into a huge loss of weight of diamond. The original shape of crude diamond determines which cut is to be performed on the diamond to achieve maximum brilliance and minimum weight loss. A crude diamond which is cut into a final diamond stone with maximum brilliance possible is called an ideal cut (well cut) diamond.

Cutting a diamond using ideal cut results into very great weight loss. So, a diamond cutter balances both the factors (brilliance and weight loss) to produce a diamond, that returns maximum value in terms of money. Also a cutter may need upto 5 times manhours to produce the ideal cut (well cut) in comparison to an average cut. When crude diamond crystal is in octahedral form (8-faces), the crystal is broken into 2 pieces and round brilliant cut is performed on it.

Why is round cut diamond more expensive than any other shape ?

Ideal cut round diamond is the most expansive diamond. This may have two reasons. First reason is that loss of weight of a crude diamond stone is more if it is cut into an ideal round shape than any other shape. Second reason is that there is more demand of round diamonds than supply. Most of people want round diamond in their engagement ring.

Who formulated round brilliant cut diamond shape?

Marcel Tolkowsky (1899–1991) is known as the father of round brilliant cut diamonds. Tolkowsky developed his ideal cutting techniques by considering mathematical formulae to produce best brilliance and fire of diamonds. He published his findings and thesis in a book called Diamond Design.

According to ideal Tolkowsky cut, a round diamond consists of 58 facets including the culet. The upper part of round diamond is called crown. Middle part of a round diamond is called girdle and bottom part is called pavilion. Crown of a round diamond acts as a receptor of light where as pavilion acts as reflector of light. See diagram:

In a crown, there is 1 table facet, 8 star facets, 8 bezel facets (kite facets or crown main facets) and 16 upper girdle facets (upper half facets). Thus a sum total of 33 facets are there in the crown of a round diamond. See diagram:

Middle part of a round diamond is called girdle. Girdle is a narrow part of the round diamond that separates crown and pavilion. Girdles may have 32, 64 or more number of facets. But these are not counted in the total number of facets of the round cut diamond. Blunt surface of girdle helps protect the edges of a diamond from chipping. A medium size girdle is desirable in an ideal round cut diamond. A very thin or very thick girdle reduces the cost of diamond. Very thin girdle will lead to chipping whereas a very thick girdle will lead to reduced brilliance of diamond. However, sometimes diamond with thin girdle is set precisely into a ring to protect the girdle. But this is not possible in case of loose diamond stone.

Bottom part of a round brilliant cut diamond is called pavilion. It has 16 lower girdle facets (lower half facets), 8 pavilion main facets and one culet. Hence it has a sum total of 25 facets. Facets at bottom of pavilion join together at bottom of the diamond to form a culet.

See diagram:

Culet is an optional tiny facet. When there is no culet, bottom surface of diamond stone will be sharp and susceptible to wearing off, if it is a loose diamond. If the diamond stone is set in a ring, sharp bottom may be properly protected in the gold. Otherwise, a small culet helps to prevent damage to the loose diamond stone. So, small culet is generally preferred. A large culet will be visible from top of the diamond ring and hence reduce brilliance.

Many old fashioned big round cut diamonds have a culet with a window (hole) extending upto table. Such diamonds are loose, they are not set to form any ring. Culet size is mentioned in a diamond certificate as none, very small, small, medium, slightly large, large or extremely large.

33 facets of crown and 25 facets of pavilion form a sum total of 58 facets. Sometimes, a round diamond may have extra facets on crown or pavilion to remove impurities on surface. This may result into deformation of symmetry.

See Video about Shape of Round Cut Brilliant Diamonds