What is a doublet in stone jewelry?

An example of a stone intarsia mosaic doublet. In this side view of the stone, you can see how it is backed with another stone for added strength.

What is a doublet in jewelry?

A doublet is a flat piece of stone that is adhered to another flat stone to create two layers of stone before the stone is shaped and polished. You often hear this stone-cutting term with opals, but a doublet could be made with any two different (or similar) kinds of stones connected.

Sometimes a doublet can be referred to as a “backed” stone, but backed more often refers to a stone—like turquoise—that has a thick protective layer of epoxy behind it.

Variscite doublet. Most doublets are made with a solid back stone backing, but I often like using some unexpected pairings, like this Dalmatian jasper. Variscite (similar to turquoise) can be a more fragile stone, so this backing helps strengthen the stone for any potential impact.

Why are doublets used?

There are many reasons why stone-cutters would make doublets. In more practical cases, doublets are made to protect a fragile or thin stone by adding a stronger, supportive stone underneath it.

Then other times, doublets are made for aesthetic reasons, like giving the appearance of a thicker stone in a tall bezel setting. Or perhaps a jeweler wants to make a reversible pendant where it features a different stone on either side.

For other beautifying purposes, doublets can be a way to add color to transparent stones (like plume agates, rutilated quartz, or the Utah-mined hyalite opal I like to use in my jewelry) by backing them with a colorful stone to create a more dimensional art stone.

A side-by-side comparison of a clear hyalite opal cabochon without a doublet backing (left) and the same kind of hyalite opal with an obsidian double backing (right). For hyalite opal, the black doublet backing gives more visual intensity to the stone’s internal refractions in the sunlight.

How are doublets made?

Doublets are made by using a flat lap to grind each of the connected surfaces completely flat before using a two-part epoxy to hold them together. Once the epoxy cures, the stone can be cut into its final shape and polished to be set in jewelry designs.

This is where gem cutting can get more exciting and really turn into an art by coming up with different combinations of stones for the most visual impact.

In-progress of making stone doublets for my Reversible Earrings.

Are doublets common in jewelry?

Opals are the most common doublets you’ll find on the market, as they have an extra added layer of complexity, know-how, and artistry to come up with eye-catching pairings. Other than that, other kinds of stone doublets aren’t that common in most contemporary jewelry designs—making them that much more one-of-a-kind.

As someone who cuts my own stones for my jewelry collections, I love that doublets are another way to be an expressive, intentional part of the design; they create even more moments of excitement when wearing it.