12 Oct 2021
Gems are extracted from the earth as rough and dull stones. Their true potential to shine is revealed only after cutting, a process that brings out the best properties of a gemstone: its brilliance, color and clarity.
Also known as faceting or Lapidary, cutting is a skilled process done by Lapidarists to enhance a gemstone’s beauty, value and price. Lapidarists use a range of tools like a faceting machine and computer aided design software such as GemCad to help gem owners plan the perfect cut for maximum value while retaining as much weight as possible.
The placement of each facet while cutting is critical in enriching the natural color of the gemstone. As color is a major value factor, the type and quality of the cut greatly affect the price.
Basic Cutting Styles
Cut gemstones come in a variety of shapes, but they all have common features like the crown, girdle and pavilion. Gemstones are cut in a way that the observer has to look through the table (the flat top facet on the crown). The girdle is the outer edge of the gemstone where metal grips clasp the stone in jewelry and the pavilion is the bottom. If the pavilion facets end in a point, it’s called a culet.
The three basic cutting styles are brilliant, step and mixed.
The table is usually the largest central facet.
Triangular and kite shaped facets.
Combination of triangular/ kite shaped facets and rectangular facets.
Also combines cabbing techniques.
Triangular and kite shaped facets.
Rectangular facets that ascend the crown in steps.
Either triangular/kite shaped facets or rectangular facets
Triangular and kite shaped facets.
Rectangular facets that descend the pavilion in steps.
Either triangular/kite shaped facets or rectangular facets.
Gives off the most scintillation of any cut.
Popular as they show off color and clarity. Also gives a subtle gleam.
Most popular cut for Sapphires and Rubies,as it brings out the best colour and yield.
These basic cutting styles are found in the standard gemstone shapes which include round, oval, cushion, pear, heart, marquise, radiant, asscher, princess, emerald, cabochon and others as shown in the image below:
At Gems Direct, we choose the following cuts to bring out the best properties of our gemstones:
Also known as the pillow cut, a cushion cut gemstone is shaped like a square or rectangle with rounded corners and sides to give it softness. The cushion cut is famous for exhibiting extremely good ‘fire’. (The fire is the brilliant rainbow effect seen in gemstones.)
Browse our collection of cushion cut gemstones here.
The heart shape is unique because of its connection to love and romance. A well-cut heart has perfectly symmetrical halves and a deep cleft between them. This shape gives off a stunning sparkle and also has magnificent fire. It looks beautiful in sizes larger than half a carat so is the perfect cutting style for earrings, pendants and large solitaire rings.
Browse our collection of heart shaped gemstones here.
Shaped like a teardrop, this brilliant cut has facets and a symmetry which reflect light beautifully. The long shape and tapering point makes it an attractive choice for rings, earrings and pendants. To prevent chipping it should be protected by a V-shaped prong in jewelry.
Browse our collection of pear cut gemstones here.
The Oval Cut
Ovals are known for their sparkle and ability to hide inclusions. A well-cut oval gemstone has an ideal proportion that minimizes extinction (or areas of blackness) which is a common effect in the oval cut. It’s an attractive shape for rings because it makes the wearer’s hand look slimmer. With no sharp corners, it’s less prone to chipping.
Browse our collection of oval gemstones here.
Fancy Gem Cuts
New gem cuts are always being developed so you can find a variety of unusually shaped colored gemstones on the market. These are usually abstract cuts and not as common as the basic cuts. These fancy gem cuts have unique features that attract customers who are looking for something even more special. However, colored gemstones are rarely cut into fancy styles.
The beauty of each fancy cut is a matter of personal preference as the standards applied to grading them are less stricter than for standard/basic cuts.
However, no matter the shape, even a fancy cut must be properly proportioned. In all fancy cuts, the girdle diameter (or widest part of the gemstone) is the foundation on which all other measurements are defined to ensure perfect symmetry. There is however, an unlimited variety of facet arrangements for a cutting style.
Evaluating the cut
While a gemstone’s color plays a major role in determining its value, the cut determines how much of that color (and brilliance) is actually exhibited. The overall quality of the cut can be categorized into native-cut, commercial cut and designer cut.
Native-cut gemstones are crude in appearance. They have asymmetrical outlines and unevenly placed, irregularly shaped facets. This is mainly because they are cut using traditional tools. Native-cut gemstones are not easy to find nowadays as they are considered ‘poorly done’ and ‘inaccurate’. Even if the stone has excellent color and clarity, its brilliance is usually muted, making buyers accidentally miss out on extremely valuable gemstones!
Commercial Cut Gemstones
The cutting quality of commercial cut gemstones is better than a native-cut. Their outlines and facets are more symmetrical and even. With more tools at their disposal, a variety of facet arrangements is possible. However, this cut is not as precise as a designer cut.
Designer cut gemstones
Designer cuts are cutting styles that are different from the more traditional facet arrangements we see on the market. They tend to be original facet arrangements until they too get copied and shared with other lapidarists. Generally though, designer cuts are distinguishable by the preciseness of the cut. There is no room for any misshapen facet!
Fantasy cuts have unusual outlines with standard or non-standard faceting. Lapidarists who prefer fantasy cuts believe the ideal proportion differs from stone to stone. Originally criticized, this cut is now admired for its originality and stands out as an art form. It looks best on larger gemstones as it gives the cutter a larger ‘canvas’ to work on.
An eye on proportions
Proportion is a very important factor in gem cutting. For instance, every cutting style has an ideal length-to-width ratio, an ideal girdle proportion, table proportion, pavilion depth etc.
Here’s a guideline of how to evaluate a basic or fancy cut (unless it’s freeform!):
Has to match the cut and be symmetrical when appropriate.
E.g. A rectangular cushion must not be ‘square-ish’ and a heart shaped gemstone must have a deep enough cleft between the two halves. If the outline is not right, it’s likely to sell for a lesser price.
Has to be centered and parallel to the girdle. If it’s too big, it can reduce the stone’s brilliance. A darker gemstone on the other hand, can be lightened by giving it a larger table.
The crown and pavilion
Good alignment between the crown and pavilion is a sign of high quality cutting.
Also avoid gemstones with bulginess in the crown or pavilion. It just adds unnecessary carat weight and cost.
The pavilion depth
The depth of the pavilion from girdle to culet should not be too shallow or the gemstone will be see-through, an effect called windowing. A window is where light simply passes straight through instead of reflecting back as brilliance.
If the pavilion is too deep, the gem appears darker, which is also a drawback.
When viewed from the top, the girdle and the table should have a symmetrical outline.
An extremely thin girdle is prone to chipping while extremely thick girdles add useless weight and make it difficult to set the gemstone.
The culet / Keel Line
Has to be centered when viewing the gemstone from the top. If it’s even slightly off-center, the gemstone is labelled as poorly cut and fetches a lower price.
The Keel Line should be of proportionate length and centered.
The optical effect of a gemstone depends on each facet having the right angle, placement and depth. Each fact is positioned carefully to minimize the visibility of inclusions and maximize brilliance.
Sharp points with the edges meeting precisely, are usually found in designer cuts. Facets without precise facet meets are common in commercial cuts but don’t reduce the value.
The number of facets ideally increases with the size of the gemstone; too many on a small stone add zero value.
A fine, even polish means there are no chipped edges or pockmarks from grinding and each facet has a mirror-like quality. It’s also proof that faceting was done properly and increases the gemstone’s value.
A gemstone has good performance if its facets reflect and refract the maximum amount of light and has no windows.
When cut with great attention to detail, a gemstone will fetch a higher price. Still, an exceptionally cut Sapphire with many inclusions will not be as valuable as a commercial cut Sapphire with remarkable color.
In the end, it all comes down to what you value in a gemstone and what you mean to do with it. Even a native-cut gemstone can look stunning when set in the right jewelry!
Visit our store to select the shape of your choice!