Cabochon cut: What are cabochons, how are they cut, and what are they used for?
- Oscar Bautista
- 3 hours ago
- 6 min read
When it comes to gems, the cabochon is the oldest cut of all.
You can recognize it by its generally convex, smooth, and unfaceted surface.
Although, as you'll see later, faceted cabochons do exist.
In my opinion, this cut is both practical and timeless, which is why I want to share some of my experience as a cabochon cutter with you.
Let's get started!
1. What is a cabochon?
By definition, a cabochon is a gem that has been cut into a rounded or convex shape on top, with a flat or slightly domed base.
Having a smooth, curved surface is important because it enhances the stone's color, pattern, and optical phenomena, as seen in fire opal.
Now, I think it's important to point out that gemstones don't come out of the mine looking like this:
"Rough" gems have their "natural" shape; then, when they go through the cutting process, they gain the shape and characteristics of a cabochon.
2. Cabochon vs. Faceted: What are the differences?
Before choosing between a cabochon cut and a faceted cut, you need to think about the gem's characteristics.
In the following table, you can see some of their differences:
Characteristic | Cabochon Cut | Faceted Cut |
|---|---|---|
Appearance and Shape | The cabochon is smooth, curved, and lacks angles on the dome (faceted cabochons being an exception). | The faceted cut has flat geometric surfaces (facets) that reflect and refract light, generating the famous "sparkle and flash.” |
Gem Type | Used mainly for opaque or translucent stones, where the goal is to highlight color, inclusions, or optical phenomena. | Faceting is ideal for transparent ("crystal-clear") gems like diamond, sapphire, emerald, amethyst, and others. |
As you can see, the cabochon cut is special for highlighting optical phenomena.
Thanks to the dome shape, light interacts with the inclusions or internal structures of the stone, giving rise to these effects:
Asterism: The "star" effect seen in some sapphires and rubies.
Chatoyancy: The "cat's eye" effect, which looks like a line of light moving across the gem's surface.
Adularescence: Refers to the floating, bluish glow of moonstone.
Opalescence: The characteristic play-of-color found in some types of opal.
Now, let's look at some of the main uses for cabochons.
3. What are cabochons used for?
Based on my experience, their smooth surface and "robust" shape make cabochons versatile and ideal for a wide range of applications:
Jewelry: They are well-suited for everyday-wear pieces, as their "softened edges" make them less prone to snagging and damage.
Goldsmithing/Metalwork: They are used to decorate objects like boxes, mirrors, or ceremonial items, providing a focal point of color and texture.
I think a great example of cabochon use is found in Colombian emerald morralla (low-grade rough).
These are opaque emeralds that don't have enough transparency to be faceted. However, they possess an intense and characteristic green color.
Therefore, by cutting them into cabochons, their color is maximized, and they can be set in rings, pendants, and a variety of other jewelry.
4. What are the shapes of cabochons?
As I mentioned earlier, the cabochon cut is quite versatile.
It can be adapted to different jewelry and metalwork projects using various shapes:
Oval: Possibly the most traditional and common shape for a cabochon.
Circular or Round: A timeless classic.
Drop or Pear: An elegant shape, preferred for many pendants and earrings.
Square and Rectangular: Usually have rounded corners for greater durability.
Marquise: The elegant oval shape with pointed ends (in some cases, the tips are softened).
Heart: For many people, this is the ideal shape for pieces with emotional value.
Trillion or Triangular: More modern shapes often used in contemporary jewelry projects.
Freeform or Irregular: Refers to asymmetrical or organic cuts that follow the natural shape of the rough stone, creating unique pieces.
Additionally, there are also faceted cabochons which, as the name suggests, have facets on the dome or across their entire surface.
Once again, the choice of shape depends on the jewelry or metalwork piece, but also on the stone's characteristics, inclusions, and optical effects.
5. Cabochon cutting: How to cut a cabochon step-by-step?
I've been cutting cabochons for over 30 years, and I still find it a fascinating art.
Here is the step-by-step process you can follow if you want to make your own cabochons:
Choose the section of the rough material that offers the best color or pattern and mark the outline of the shape you want to get.
Cut the basic shape of the cabochon from the rough stone (I use a machine with a diamond saw blade).
If the gem is small or delicate, attach it to a wooden or metal dop stick using dopping wax; this way, you can handle it more securely.
Use a coarse-grit grinding wheel or lap (220, 280, 600) to rough out the stone, shape it, and refine the outline.
Continue sanding with progressively finer grit wheels or laps (1200, 3000) until the surface is smooth and free of scratches.
Use a felt or other material polishing wheel along with an abrasive (like cerium oxide or diamond powder) until the stone achieves its final shine.
Remember that while it is possible to make cabochons at home, using a specialized gem cutting service offers several advantages:
Precision in shape, the possibility of calibration, the experience to orient gems that show optical phenomena, and a high-quality polish thanks to professional machinery.
5.1. Techniques for cabochon cutting
Beyond the fundamental steps, here are a couple of techniques you can keep in mind when making a cabochon:
When dealing with asterism or chatoyancy, you must orient the rough stone so that the base of the cabochon is parallel to the inclusions. This ensures the optical phenomenon is centered and sharp on the cabochon's dome.
The secret to a "mirror" polish lies in patience and the selection of supplies. You must use the sanding grits, laps, or wheels gradually until all scratches disappear from the stone, and use the appropriate abrasives.
Now, to finish this section on processes, let's move on to accessories for cabochon cutting.
5.2. Accessories for cabochon cutting
These are some of the accessories for cabochon cutting that I use daily in my workshop, and that you might find useful.
First, review what you need and compare the different options on the market before making your purchase decision:
Accessory | Description | Can be purchased on |
|---|---|---|
Dopping Wax | Use this to adhere the stone to the dop; different colors (red, brown, and green) indicate different melting points. | Specialty stores |
Dop Pot | A small electric pot that keeps the wax at a constant, safe temperature for use. | Specialty stores |
Alcohol Lamp | You can use this to melt the dopping wax (in my opinion, it's the best alternative to a dop pot). | |
Metal or Wooden Dops (Dop Sticks) | These are sticks of different sizes, on which you attach the gem to handle it during cutting | Specialty stores |
Dop Station | A stand that helps you keep your dops organized and upright while the wax cools or between work sessions. | Specialty stores |
10x or Higher Loupes | Use these to inspect the stone for fractures and to check the quality of the polish. | |
Headband Magnifier/Visor | You can use this as an alternative to a loupe; being a headband visor, it allows you to keep your hands free for cabbing. | |
Digital Calipers | Necessary for cutting cabochons to specific measurements or for cutting two or more calibrated cabochons. | |
Cabbing Machine | A machine that holds several grinding and polishing wheels, specially designed for making cabochons. | Specialty stores |
Cabochon Templates | Plastic or metal stencils with specific shapes and sizes for marking the outline on the rough stone; their use is optional. | Specialty stores |
I hope this guide has been helpful for you in making informed decisions about cabochons.
