cut flaws

The Aurore is special to me in a lot of ways, but especially because it was designed specifically for a stone that I had loved for a long time, but it’s many issues prevented me from setting it.

By now, I think that if you have taken a look at my designs, you’ve noticed that diamonds are almost always accent stones. That’s not to say that I won’t set a diamond, but I put a lot of special consideration into making jewelry with colored stones.

Colored stones have their own potential problems when it comes to producing a setting for them. For instance, colored stones are typically cut with two things in mind: color and size/weight retention, which come with their own host of issues, typically windows (an area that doesn’t reflect light), which is what the Aurore was specifically designed around.

Naked sapphire.

I designed the Aurore setting around a padparadscha sapphire I have had for a while, but could never figure out how to set. The stone has a big window in the middle of it due to insufficient depth. Diamonds don’t typically have that problem, it’s a uniquely colored stone issue. The stone has an amazing color, though, and obviously the best was made of the material by the cutter. It also has some inclusions in it, which give it more of a glow and less of a sparkly bomb.

My solutions to the various problems presented in this particular stone was to start from the bottom and work my way up. The Aurore has a lotus design on the bottom, inspired by the very color of the sapphire, giving the basket some decent coverage, which would help close up that window and let the stone shine.

pad3
Early sketch ideas.

But I didn’t want to just stop there – I had a parcel of marquis diamonds, what if I set those inside the lotus petals on the basket. Then, light hitting the pavilions of the diamonds would potentially reflect light up through the stone!

Taken a very long time ago!

I would want the lotus petal design to be seen, and the diamonds would of course need lots of light to have that function properly. So a traditional fully round shank was out. Which meant it was time to think outside the box, and the partly open shank, that isn’t a complete circle. And now, we can see the full view of the lotus and diamonds.

So I then turned my attention to the top of the ring. The stone only measures 5×7, so, I decided that it needed a little bit of help in the size area. Well, since the stone is windowed and not super sparkly, a traditional diamond halo ran the very real risk of outshining the center stone, instead of fully enhancing it. I saw Erika Winters’ Thea halo, and thought, “Hey, why can’t it be all metal? No reason to include diamonds.” And again, taking inspiration from Erika’s Thea halo, and due to the smaller amount of sparkle from the center, decided against high polish, and went with a matte finish.

But a plain metal halo would be boring – so since I had become vehemently against putting the sapphire against diamonds, that meant metal detail. I got the inspiration for the shapes from an antique diamond and emerald ring. The shapes are different, but the idea for the layout is similar.

All in all, I was so satisfied with the first version of the ring, I decided to go to the opposite side of the color spectrum and do a white metal version.

In doing a second prototype, the gray spinel’s window was much smaller, so I decided to forgo the diamonds on the gallery. But instead of keeping the entire thing with a matte finish, I decided to have my bench put a high polish on the metal halo’s details. Which really lends a beautiful effect and mimics the sparkle of the silvery spinel even more wonderfully than I could have imagined.

Keeping the white gold with a matte finish was a bit of a gamble, because I wasn’t sure what kind of effect it would have due to it’s gray color, but looking back, it wasn’t something I should have worried about – as a whole, the silvery gray spinel appears even more sparkly surrounded by the contrast of the matte and high polished metal.

All in all, the Aurore is a setting I’m proud of. There is something very fulfilling about creating something to solve problems, no matter how small, and further enhancing the beauty of what is already there.

The Aurore is available for order directly through me, or through David Klass in Los Angeles.

Most gemstones on the market are either cut by machine or cut on rudimentary machines. As a result there are a lot of gemstones out there that have a lot of issues and in my opinion, are less beautiful.

I had mentioned in this post, Considering Gemstone Recuts, about recutting two stones for repair, and one for appearance sake. I would like to go a bit more in depth as to what these cut flaws can look like, and why they are considered flaws.

Please note that I am not a lapidary and do not have as stringent guidelines as they might for what makes a beautiful gem.

Windows

Windowing in gemstones is when the gemstone has what looks like a hole in the middle and the stone is completely see through without sparkle in the middle. What is happening here is that the facets on the pavilion of a stone is cut to such an extreme angle, so that the light goes into the gemstone, and straight back out the bottom. These facet angles on the pavilion can run almost parallel to the table of the gemstone. Here is a good example of a windowed gemstone:

Windowing can occur two different ways, the first being when the gemstone is cut too shallow, typically to preserve a larger face up size for the stone. This cut flaw cannot typically be corrected without significant loss to the faceup size of the gem. This can also affect the value of the gemstone in a big way, losing valuable carat weight and face-up size.

The second occurs when a stone is cut at the wrong angles for the gem variety. The stone typically has a “fat belly” or “fat pavilion” or looks rounded on the bottom, more like a ball than coming to a sharp point, or culet, the way you would expect a gemstone to be cut. These stones are typically cut for weight retention. Here is the stone from my previous post that has this flaw, a silver spinel:

A deep belly/pavilion can typically be corrected with some tweaking by a talented gem cutter.

Tilt Windows

Tilt windows can be seen in every single gemstone variety, including diamond, but are most often seen in stones that have a lower refractive index, such as tourmaline, topaz, quartz and beryl. Tilt windows can be seen when a stone is being viewed from an angle that isn’t straight on. Stones with lower refractive index will show windows more easily. Please note that all of the stones seen in the following examples are cut by talented precision lapidaries.

Tourmaline tilt window:

Slight tilt window seen on the left side of the garnet in this picture:

Slight tilt window in a asscher spinel:

Extinction

Gemstones can be cut to incorrect angles to the point where they black out, or when light goes in, but does not get reflected back to the eye. This type of problem is called extinction, and is a serious flaw because if a stone looks black instead of being a nice color, what’s the point? Some gem cutters expressly cut stones so that facets take turns turning off and on, this effect would be considered being cut for contrast, rather than plain extinction.

The dark blue spinel on the bottom is showing a bit of extinction, while the stones above it (sapphire and spinel, respectively) are not.

Half and Half Shadowing

Half and half is typically another result of less than ideal cutting, and is also a mechanism of physics. It’s a specific type of extinction, so it is a result of light going into a stone and not being reflected back to the viewer’s eye. However, this particular type of extinction is typically seen in an elongated brilliant cut stone such as cushions, radiants and ovals. When these stones are viewed North-South, the phenomenon is very visible, but when the stone is viewed East-West, it can become essentially non-existent.

The dark blue spinel (same from above) on top shows it’s dark side on the upper half.

A purple sapphire shows some half and half darkening on the top half of this stone.

This stone is a spinel, and you can clearly see the half and half as well as a bit of a tilt window.

So, while none of the above are deal breakers when I look at a stone, they are still qualities to take into consideration when purchasing gemstones and looking for beautiful jewelry. Any gemstone variety can have the above cut issues, they are not limited to any one particular gem over another. One way to mostly bypass these issues is by finding a lapidary and checking out their inventory, but that is not a guarantee!

The Aurore Setting Design Process

Gemstone Cutting Flaws