Coloured Stone Cuts and Shapes
The word lapidary (adj.) relates to the work of cutting, grinding, polishing, or engraving precious stones, mostly other than diamonds. It is a process that turns a coloured precious or semi-precious rough stone into a beautifully shaped gem to use in jewellery. A well-cut stone helps to hide imperfections and bring out its true colour and brilliance. Broadly, there are two styles of gem cutting – faceted and non-faceted, or cabochon. While faceted gemstones have geometric shapes and flat polished surfaces, cabochons have rounded surfaces. Today, fancy cuts such as flowers, leaves and stars can also be seen in coloured stones. It is the artistry of the gem cutter or lapidary (n.) that makes each coloured gemstone a piece of art.
Here are some of the most common cuts used in gemstones:
1. Cabochon Cut
The cabochon, also known as a cab, is the oldest form of shaped and polished gemstone dating back to the 13 or 14th century. The name, derived from the Norman French word “caboche”, meaning head, describes the stone as having a flat bottom with a convex or rounded domed top. The cut helps to display characteristics like asterism (the star effect) in star sapphires and rubies, chatoyancy (Cat’s Eye effect) in tourmalines, Tiger’s Eyes, chrysoberyls, iridescence (changing of colour in some lights or angles) in opals, or adularescence (milky-bluish lustre) in moonstones, rose quartz and agates. While the traditional cabochon was oval in shape, today cabochons are available in rounds, triangles, and rectangles.
This cut is a mix of a cabochon and a faceted gem. The top has a cab dome while the bottom contains facets on the pavilion below the girdle. These strategically placed facets allow light to reflect from the pavilion, giving the gemstone an illusion of depth. Bufftops are often found in men’s jewellery. This kind of cut is exactly the opposite of a rose cut.
3. Round Brilliant-Cut
The round brilliant-cut gemstone, also known as the Round Cut, American Ideal Cut or American Standard Cut has 57 facets. It was perfected by mathematical genius Marcel Tolkowsky in 1919, calculated with variables such as the index of refraction and covalent bond angles. Today, the best diamond solitaires in the world use this cut. Tolkowsky’s recommended cut height for a Round Brilliant is 58% of the diameter of the diamond, 43% for the pavilion, and 14% for the height of the crown. This ratio provides maximum fire, brilliance and sparkle. This cut is also commonly found in coloured gemstones.
4. Oval Cut
The Oval cut has an elliptical shape with 69 facets. Created in the 1950s, it is a hybrid between a round cut and a marquise cut. Often used in coloured stone and diamond engagement rings, the elongated silhouette of the gemstone creates the illusion of a larger gemstone allowing the finger on which it is worn to look longer and slimmer.
5. Baguette Cut
Long, oblong and rectangular-shaped Baguette cut gemstones first appeared during the 1920s-30s art deco movement. Crafted in step cuts the 14 facets resemble a pyramid without a top. It has clean lines and a modern, geometric look. Baguette cut stones can be either regular or tapered, resembling a trapezoid.
6. Princess Cut
The Princess cut, or Square cut, is the second most popular cut, after the Round Brilliant cut. It is technically known as the Square Modified Brilliant because it is a square version of the Round Brilliant cut. It has between 58 and 76 facets that give it brilliance and sparkle and maximize its lustre. A square-cut gem retains 80% of the rough gemstone. Solitaire engagement rings have princess cut gemstones with trilliants at their sides.
7. Pear Cut
A Pear cut gemstone looks like a teardrop. It offers 71 facets that reflect light and allow the colour to showcase dramatically. It is a difficult cut that needs an expert lapidary to align the point with the peak of the rounded end. The gemstone also requires a six-prong setting to maintain support for its fragile point. Pear cut coloured stones have donned jewellery since the 1400s and are a favourite in earrings and pendants even today.
8. Emerald Cut
The Emerald cut is like a rectangle from the top, except that it has trimmed or truncated corners. Its 50 facets help to emphasize the gem’s colour and clarity. The cut was originally designed for emeralds. Since
emeralds occur in nature with numerous inclusions and are softer than other precious stones, cutting them was difficult due to potential chipping. The Emerald cut addressed those issues by decreasing the amount of force applied during cutting to protect the stone from chipping and breakage.
9. Octagon Cut
The Rectangular cut or Octagon cut gemstone has 53 facets. This cut is different from the Emerald cut as the steps on the pavilion are not equidistant. In this cut, the four corners are metered and the facets run in steps parallel to the gemstone circumference. It is also a preferred cut in which the deep colour highlights the beauty of the gemstone.
10. Cushion Cut
This classic Cushion cut has 64 facets. Also known as the Pillow cut, Old Miner cut, or Old European cut, the Cushion cut was popular in jewellery of the late 19th and early 20th centuries. Like a Princess cut, this cut also reduces the wastage of the rough gem while maintaining its lustre and brilliance.
11. Marquise Cut
The Marquise cut, also known as the Navette cut, has 57 facets. This modified brilliant cut has a ratio of length to width 2:1 to help reflect the most amount of light and maximize sparkle and colour. In a Marquise cut, the two endpoints must line up with each other and the two halves of the stone should be perfect copies of each other. The cut offers more weight per carat than any other cut creating an illusion of a larger gemstone.
One of the most difficult shapes to cut, the Briolette cut is a pearshaped or drop-shaped stone. It has 84 triangular-shaped facets covering its entire surface that help to reflect light. There is no table, crown or pavilion. Most briolettes are drilled with a hole through the top to allow a wire to pass through. The Briolette cut is said to have originated in India as early as the 12th century and then introduced in European jewellery by the famous French trader and traveler Jean- Baptiste Tavernier.
13. Heart Shape Cut
The ultimate symbol of love, the Heart Shape cut, resembles a pear-shaped gemstone with a cleft at the top. The Heart Shape cut gemstone has 59 facets and its length to width ratio is 1.1:1. The cut must ensure two symmetrical halves, a sharp and distinct cleft and slightly rounded sides. Heart-shaped gemstones remain a popular choice for Valentine’s Day.
14. Trilliant Cut
The Trilliant cut was designed in Amsterdam and later trademarked by the Henry Meyer Diamond Company of New York in 1962. It is triangular in shape having between 31 to 43 facets. The tips and culets of Trilliants are pointed and thin. Variations include roundedcorner triangles, modified shield cuts and triangular step cuts. As Trilliants return lots of light and colour, they are used as side stones in modern jewellery settings.
15. Millennium Cut
The Millennium cut was created by Rogerio Graca in 1999 to symbolize the new millennium. This cut has an incredible 1,000 facets, requires high precision machinery and takes 18 times the amount of work of other cuts. Due to these factors, it is only available in limited numbers.
Now that you know your coloured stone’s cuts and shapes – Happy Shopping!
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