An Introduction to Fancy Gem Cuts

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PinkDiamond
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An Introduction to Fancy Gem Cuts

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Here's the 3rd of the 3 articles on cutting that I said I have for you in the first article I posted from the International Gem Society today. This one has the really odd cuts that I'm sure many aren't aware of. You'll notice I added my own emphasis over the "Pink Dream". :lol: Enjoy! :)

An Introduction to Fancy Gem Cuts
by Phoebe Shang, GG, International Gem Society

Step 1: Introduction to Gemology
Lesson 24


Summary

The cut is humanity’s contribution to the beauty of gemstones. Color, clarity, and carat, the rest of the 4 Cs of gem grading, come mostly from Nature. What we call the cut not only determines how precisely a finished gem is fashioned but also its shape. Although rounds and other standard shapes have long dominated the market, fancy gem cuts offer many alternatives.
Reading time: 13 min 36 sec


Image
This 0.12-ct fancy intense blue green oval diamond by Leibish & Co has a rounder and squatter shape than most oval cuts, a type of fancy gem cut. This gem also has undefined heads on both ends. Photo by Fancy Diamonds, Leibish & Co. Licensed under CC By 2.0.

"What are Standard Gem Shapes?

For faceted gems, standard shapes include rounds, squares, and rectangles. For cabbed gems, rounds and ovals are standard shapes.

Rounds have dominated the faceted gem market since the 1880s when Tiffany and Co. created the six-prong setting so often seen in solitaire rings now.

Image
A diamond solitaire set in yellow gold. Photo by Cs1791. Licensed under CC By-SA 3.0.

The development of the modern round brilliant cut has made rounds more dazzling than ever before. As a result, rounds have become more popular.

What are Fancy Gem Cuts?

Despite the dominance of rounds, fancy gem cuts still hold their own. Customers looking for something unique, symbolic, or vintage can turn to these different cuts.

For faceted gems, a fancy cut is any cut other than a round. This category includes ovals, pears, hearts, and other cuts, too.

Fancy cab shaped gems are anything other than a round or oval. They include rectangles, squares, crosses, tear drops, and freeform shapes.

Image
A variety of diamond fancy cuts with facet charts. Image by Open School of Diamond Gemology. Licensed under CC By 3.0.

The beauty of each shape is a matter of personal preference. However, in several respects, fancy gem cuts have advantages over rounds:

* When compared to a round of the same carat size, fancy shapes will look larger face-up and have lower prices.
* Rounds sell at premiums due to their popularity and the fact that faceters must discard more rough during the round cutting process.
* Rounds don’t make ideal shapes for gems past three carats in size. Enormous circles aren’t attractive. Enormous hearts or pears, on the other hand, look perfectly beautiful.

Here is a breakdown of the most commonly seen fancy gem cuts in approximate order of popularity.

Cushion Cut

The cushion cut, also called the pillow cut, is essentially a square with rounded corners and sides, like the cushions of a couch.

Image
This 1.13-ct. benitoite color suite features square cushion-cut gems, from deep violet to colorless. © The Gem Trader. Used with permission.

The cushion cut has large facets. This means, despite being a brilliant cut, it returns less light than a round brilliant and has a blockier light return pattern. While this quality gives cushions a vintage feel, it also makes them unforgiving with flaws. Any inclusions will be clearly visible through these large facets, which act as windows into the stone. White diamonds will also show any color. One advantage of the cushion, however, is that it has more fire than other cuts, including the round.

While most cushions are squares, some are rectangular. The ideal ratio for rectangular cushions ranges from 1.15 to 1.20. A rectangular cushion should be long enough to be clearly distinguishable from a square but not too long and narrow.

Oval Cut

The elegant oval cut is particularly suitable for rings. The shape makes the wearer’s hand appear slimmer. Plus, since the cut contains no sharp corners, the stone runs less risk of chipping.

Image
Oval-cut diamond solitaire. Photo by Dublin Diamond. Licensed under CC By-SA 4.0.

Modern ovals are cut in the brilliant style with 58 facets. Because they have more sparkle, ovals hide inclusions much better than cushions. This holds especially true around the “head” or “end” of the oval, where the facets gather more tightly.

Image
Image
The 24.78-ct oval “Pink Dream” diamond is the largest internally flawless pink diamond graded by the GIA. It sold for $83.2 million in 2013. Photo by Diamondhistorygirl. Licensed under CC By-SA 4.0.

The oval cut does have a fatal flaw. It exhibits a type of extinction known as a bowtie, a dark band across the middle of the stone caused by poor light reflection and the viewer’s shadow. Each oval stone will have one. While barely perceptible in well-cut ovals, they appear ruinously in poorly cut stones.

The ideal proportion for ovals ranges from 1.30 to 1.50. In addition, make sure the shoulders on an oval are neither too “high” and bulging nor too flat. Both make for an unattractive stone, and bulging shoulders hide weight.

Image
This 0.50-ct oval fancy intense blue diamond (SI2 clarity) is an example of a longer, thinner oval than typically seen. It also has a flat shoulder, most likely cut to save weight. Photo by Fancy Diamonds, Leibish & Co. Licensed under CC By 2.0.
Image
Oval-cut iolite, Madagascar, 3.46 cts. © All That Glitters. Used with permission.

Princess Cut

Invented in the 1960s, the princess cut is essentially the square version of the round brilliant. It enjoyed popularity for decades due to its brilliance and modern look. Its sharp edges mean that faceters can retain more rough during the cutting process. As a result, princess cuts are much more affordable than rounds.

Image
2.65-ct princess-cut diamond solitaire ring. Photo by TVZ. Licensed under CC By 2.0.

The princess cut does have a drawback. Its corners make it prone to chipping. Jewelers must make sure to protect the corners.

Image
A close-up of a princess-cut diamond solitaire ring. Photo by Stephen Durham. Licensed under CC By 2.0.

Image
Loose princess cut diamond with chevron pattern clearly visible through the table. Photo by Mark Johnson, Serendipity Diamonds. Licensed under CC By-ND 2.0.

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Facet charts comparing princess cuts with 3 chevrons (top) and 4 chevrons (bottom). Image by Anniewill. Licensed under CC By-SA 3.0.

Emerald Cut


Although named after the emerald and often used on those gems, emerald cuts are applied to many gemstone species.

Image
Precision set emerald-cut diamond ring. Photo by Woodysjewels. Licensed under CC By 2.0.

Known for its “hall of mirrors” effect, the emerald cut creates this dramatic pattern by alternating lines of light and dark. This effect is caused by step cuts, straight cuts parallel to the stone’s girdle, which are clearly visible through the stone’s large table.

Image
Natural loose emerald-cut diamond showing extinction. Photo by Petra Gems. Licensed under CC By-SA 4.0.

The emerald cut isn’t as fiery or sparkling as most other cuts. Instead, it reflects light in sheets, creating a clean, elegant look. However, since it has the largest table of all fancy gem cuts, it’s also the least forgiving of inclusions. Any flaw will be clearly visible, and white diamonds will also show any color.

Image
Emerald-cut green tourmaline, 3.92 cts. © All That Glitters. Used with permission.

Emerald cuts feature beveled corners. Ideally, faceters should make the bevels wide enough for setting prongs to fit securely but not so wide that they detract from the rectangular appearance of the stone.

An emerald cut’s pavilion should also be angular and tapered rather than curved. Narrow bevels as well as bulging pavilions increase the carat weight without increasing size. Bulging pavilions also decrease the brilliance of the stone. The ideal proportion for an emerald cut ranges from 1.40 to 1.50.

Image
A ring with an emerald-cut emerald flanked by emerald-cut diamonds. Public domain.

Baguette Cut

Related to the emerald cut, a baguette cut is a rectangular or trapezoidal step cut but with fewer facets and no bevels.

Image
Sapphire, fancy radiant cushion baguette cut, 3.26 cts. © Dan Stair Custom Gemstones. Used with permission.

Radiant Cut

Just like the ... "

https://www.gemsociety.org/article/fancy-gem-cuts/
PinkDiamond
ISG Registered Gemologist


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Re: An Introduction to Fancy Gem Cuts

Post by SwordfishMining »

Thanks for sharing again.
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