Most diamond jewelry collectors are probably aware of the common cutting styles usually applied to their gemstones. The famous round brilliant cut is also most often the priciest among the modern-cut shapes, all things equally considered.

A round brilliant cut diamond consists of 57 to 58 facets. The last optional 58th facet would be the culet- a small polished facet at the pavilion point area. This was originally done to prevent point chipping, however larger culets are a lot less commonly seen on most newly cut round brilliants today.

A facet is a small polished surface. Brilliant cut diamonds are created with triangular or kite-shaped facets that cover the entire gemstone's surface. Facets allow us to better view the scintillation and brilliant beauty of a diamond, while providing us with many windows to look into its transparent body as well.



Emerald cut and Asscher cut diamonds are created with step-cut facets instead of brilliant facets. This means that their facets are usually four-sided shapes such as trapezoidal designs, rather than triangular. While some people prefer step-cuts for their diamonds, it all depends on the visual effect desired for the stone.



Brilliant cut stones, as the same suggests- show more sharp and numerous brilliant reflections. They also heighten color dispersion or 'fire' as most people term it. The round brilliant style is very specific in its ideal proportions, which is why different laboratories also assign a cut-grade to these stones, as a way of judging how well their cutting accentuates the gem's optical beauty.

Step-cut stones are often done on diamonds with very high clarity, as a way of visually showcasing the top-notch grade through an absence of inclusions. For colored stones on the other hand, a mix of brilliant and step-cut facets is preferred by many. This style is what's referred to as a mixed-cut. More often than not, mixed cuts use a brilliant cut crown with a step-cut pavilion. The latter helps to save weight from the raw crystal.

The term mixed-cut though can also refer to other combinations of faceting styles. Combined with the current diversity of shape choices, the gemstone industry actually has a very wide array of gem cutting designs to suit anyone's personal taste and preference.

You would almost never see a standard-sized diamond cut in a mixed-cut style because it just doesn't bode as well with diamond's optical properties, as the traditional full-brilliant cuts do.



Specific angles and facet placements are needed to direct light from the stone, back into your eyes in the form of brilliance and sparkle. Light leakage can occur if the diamond is either too shallow or too deep, resulting in either a watery-looking effect with grayish girdle reflections, or a darkened center area known as extinction.

The round brilliant style has been very popular for several decades now, despite newer more proprietary cuts coming into the market. Some diamonds are even cut with over 200 small facets to create a novel appeal.

Well today let's take a look at a handful of faceting styles and shapes that have captured the market's attention for best displaying the appeal and beauty of a gemstone. First off, probably the most utilized cut for rubies and sapphires (non-melee) would be the oval mixed-cut. The mixed faceting style simply refers to a gem that has both the brilliant-cut faceting style (triangular & kite shaped facets) and the step-cut faceting style (four sided facets). One might be on the crown, the other may be on the pavilion, or the reverse can also be true. This particular cutting style allows gem cutters to save weight from the original crystal, by cutting with a bit more bulge, especially if cutting the pavilion as a step-cut. Unlike diamond, the focus for colored gemstones is more about the intensity of color, and adding more material intensifies the selective absorption process that expresses a stone's color to our eyes. (Image credits to Sotheby's Auction House)

While rubies and sapphires are very often cut as mixed cuts, another very popular cutting orientation would be what the industry calls the 'Emerald Cut', which as you might have guessed, is very popularly used with emeralds. This is mainly because of how emerald crystals grow. Compared to the common tabular shapes of rough ruby, emerald crystals tend to grow as hexagonal prisms, or at least in elongated formats. The Emerald cut is a rectangular step-cut style that makes use of bevelled edges, and it's been the number one choice for emerald gemstones for a long time now. Even diamonds have adopted the appeal of this cut, because it accentuates their transparency and clarity, while presenting a very bold elegance and feel.



While the two styles above are probably the most popular choices for colored stone cuts today, another forerunner would be the cushion cut. Now the cushion cut is a little less defined than the previous two we mentioned. There are square cushions and rectangular cushions, as well as other shapes and varieties. The main difference between the cushion cut and other cuts, lies in the fact that cushion cuts have curving edges on all sides when seen face-up. It sort of resembles a pillow, or a cushion in shape outline- hence the name. This cutting preference allows a good amount of weight to be saved, and just like the standard oval mixed-cut, this appeals well for gem-cutters due to the fact that color can be better shown with more material.

Colored diamonds are also often cut into cushion shapes. The 'oval' or 'stadard' cushion cut pink diamond, pictured below, is a prime example of this. Color will always be one of the defining factors in gemstone valuation- whether it be the presence of it or the absence of it.



Each gemstone can be cut in a huge variety of choices. Emeralds can also be cut as mixed-cuts, and star rubies & sapphires can be polished into cabochon cuts. There are so many choices for gemstone appearances in today's trade, that the main factor to consider is your own personal preference. Brilliant faceting styles create sharper, more crisp brilliance patterns, while step-cut faceting styles can save more weight, and deepen color. Proportions and angles are also equally important so as not to create areas of windowing or extinction, where light can leak out of the stone rather than bounce back to the viewer's eye.

Here we'll just briefly discuss some of the commonly misunderstood concepts observed in the local trade. Now, certain people may already be aware of these, but it seems that every now and then some people express confusion regarding what many terms mean, and what they don't mean. This short article should give you a bit of insight (and trivia) about gemstones and jewelry.


1. 'Emerald Cut' refers to a specific cutting style and shape, not necessarily or specifically to the emerald gemstone itself. Most diamond collectors may be familiar with the popular term 'emerald cut', but some people are not aware that this term refers to how a gemstone (diamond or any other) is fashioned and polished into a rectangular shape with step-cut (four sided) facets on its body. Emeralds themselves, are very often cut in this rectangular style, because of the way their crystals grow, and the intention of gem cutters to save the most weight. Today, many other gemstones, such as aquamarine, diamond, amethyst and quartz are frequently fashioned as 'emerald cuts'. This specific cutting style is well suited for stones of high clarity, or stones that tend to form elongated or columnar in nature.


2. Rubellite is not ruby. We've come across a few parties that previously believed rubellite to be a form or type of ruby. This is simply not true. Rubellite is a trade named color variety for red to pinkish red tourmaline. Both tourmaline and ruby maintain very differnet gemological properties, and prices. Ruby is traditionally much more expensive than rubellite tourmaline, given a situation where color intensity and clarity levels are generally equal.


3. The term 'synthetic' is different from the term 'imitation' or 'simulant'. A synthetic gem refers to a man-made counterpart of that gem, with the same essential crystal structure and chemistry. A synthetic diamond, is still made of carbon, crystallized in the cubic crystal system for example. This is in stark contrast to an imitation gem (also called a simulant gem). An imitation gem merely looks like the gem it is trying to copy. Moissanite for example, is an imitation of diamond, as it is made of silicon carbide instead of pure carbon. It also grows in a different crystal system.


4. Cultured Pearls, not wild pearls, comprise a majority of all middle to high-end pearl jewelry collections in the country. Some people are not aware that over 99% of all pearls used in the jewelry industry today (especially the mid-to-high ranges) are actually cultured pearls. Cultured south sea pearls for example, are among the most expensive pearl items you can procure, with some necklaces costing hundreds of thousands of dollars. For pearls there are three categories you have to be familiar with. Imitation pearls, cultured pearls and wild-caught pearls. Imitation pearls are simply simulant items usually made of plastic or glass coated with iridescent substances. Cultured pearls and wild-caught pearls both come from actual live animals (mollusks, oysters etc), but a cultured pearl means that man has assisted the developmental stage by putting either a piece of mantle tissue or a shell-bead nucleus inside the mollusk in order for it to coat with nacre over long periods of time- to eventually form a pearl. The nacre layers are still organically produced by the same animal. Wild-caught pearls statistically speaking, are rare coincidences in nature today, and almost never come in large enough symmetrical shapes (round, oval etc.). The vast majority of fine pearl jewelry makes use of cultured pearls. (This statement does not apply for giant clam pearls, which we do not currently test at the laboratory).


5. Diamonds are not indestructible. We would not suggest that people perform any possibly-destructive test to find out if their stone is actually a diamond. Stories of sandpaper-scratching or hardness testing using rocks or other materials seem to be very prevalent among Filipinos. While diamond is the hardest mineral to 'scratch', it does maintain multiple planes of atomic weakness (cleavage). When struck in specific directions, a diamond can chip, fracture or even split in two. Thin areas of a diamond, like its girdle or culet, are also very prone to breakage. This can still happen even if it impacts with something with a generally lower hardness, if done in certain ways. Additionally, diamonds can also burn if subjected to high enough fire temperatures and sufficient levels of oxygen (because they're still carbon).


6. Proper heat treatment in rubies and sapphires is okay and an accepted part of the trade. There are those out there who detest the thought of their rubies being treated, but the vast majority (over 95%) of rubies and sapphires today are actually subjected to some form of heat treatment. It's a normal practice in the industry, and can bring out a stone's potential when done in the correct conditions using appropriate methods. While premium prices do exist for unheated stones, it's just as likely that an originally duller stone's value can eventually be heightened by subjecting it to heat treatment and increasing the overall color quality.


7. Glass-filled rubies are not nearly as expensive as natural or heated-only rubies. These items can be filled with glass in up to 50% of their composition. If someone tells you that their value is basically the same as rubies that aren't filled, you should probably do a bit of research first. Most likely you'll find that glass-filled rubies were originally very opaque-looking low-quality stones. Their durability post-treatment is also not that stable, according to many of our visitors and our own observations.


8. DIY Handheld Diamond Thermal Testers cannot differentiate between natural diamonds and lab-grown / man-made diamonds. These instruments make use of a technology that measures thermal conductivity, a property that is essentially the same for both natural and synthetic diamonds. Other testers like duo or multi testers that also check for moissanite, make use of electrical conductivity. These also cannot separate CVD or HPHT lab grown diamonds from natural diamonds. Advanced spectrometric testing is more suitable for this differentiation, which we make use of here at Gemcamp Laboratories.