Professional Jeweler Archive: Sizing Rings Set with Lab-Created Moissanite

February 2003

Professional Bench/Manufacturing Up Close


Sizing Rings Set with Lab-Created Moissanite

As the use of this stone in fine jewelry grows, here are some tips for working with it at the bench


One-third of a bench jeweler’s daily job assignment at the retail level is typically related to sizing rings. With growth in the sales of created moissanite jewelry, it’s important for bench jewelers to know how to identify and work with the material through the sizing process.

Inspection and Identification

The first step at the bench is to inspect all incoming jewelry before working on it. Look through the crown facets of created moissanite using a 10X loupe and you will see a doubling of the back facets as shown above.

Photo by Earl Hines, vice president of production Charles & Colvard.

Sizing Rings Set with Lab-Created Moissanite

As reviewed in the December 2002 (pp. 76-77) and January 2003 (pp. 94-95) issues of Professional Jeweler, this stone is very tough, durable and tolerant to heating at soldering temperatures. When sizing rings set with created moissanite, you will have no problems and see no damage to the stones using standard torch techniques.

This ring needs to be sized down one size. After cleaning, a routine inspection reveals it’s secure in the bezel. No previous damage to the stone or the mounting is evident.

Here are the steps to follow:

1. Check for previous solder joints. One method is to heat the ring with no firecoat solution applied to it (denatured alcohol and powdered boric acid) using an oxidizing flame at the bottom of the shank. With sufficient heating, a line will appear (A) across the shank.

2. If you locate a previous solder joint, saw through it first. If not, saw and remove about a 2.25mm size piece in the narrowest width at the bottom of the shank. This will leave room for filing and truing. Be careful not to remove a hallmark or special engraving.

3. File and true the butt joint as necessary. Carefully realign the two cut sides of the shank and make sure they’re aligned from all views.

Note: Soldering a misaligned shank will cause you to file away too much metal in the finishing process, removing several years of wear.

4. An ideal solder joint is one where each side of the shank is in contact and perfectly flush. No light or obstructions are visible through the seam when the joint is inspected thoroughly with a 10X loupe.

5. Hold the ring using cross-locking or other soldering tweezers. In the example at the top of the next column, notice how the tweezers hold the ring and stone simultaneously. This technique will help protect any stone from excessive heat. Don’t try this technique on soft stones because they will scratch easily.

6. Hold the ring with the bottom of the shank facing upward.

Note: Because heat rises, this technique will allow it to conduct upward through the joint heating the ring to soldering temperatures.

7. Preheat the ring. Place a chip of hard solder in flux then across the joint on the top of the shank. The flux should cause it to stick in location.

8. Heat the ring from the inside of the shank facing the torch upward. The hottest part of the flame is just beyond the cone. Position the cone about 1/4 inch from the solder joint and slowly move it back and forth to heat evenly. When the ring is heated in this area to soldering temperatures, the solder will melt and flow and be drawn downward, rejoining the shank.

Note: Improper torch technique will cause the solder to flow over the surface of the ring’s solder joint, giving it the appearance of being fully soldered. This type of joint is void of solder in the central area and will break open during normal wear.

Joseph Bacher, president of the Illinois Jewelers Association and owner of J. Bacher Fine Jewelry Designs, IL, has been designing and manufacturing jewelry containing created moissanite for more than five years. To date, he’s sized hundreds of his company’s creations for customers and has not experienced damage or related problems to the stones. He confirmed the use of the standard techniques outlined above as the methods he uses for sizing.

Lab-created moissanite educational content is sponsored by Charles & Colvard Ltd. For general information related to Charles & Colvard and created moissanite, call the company at (800) 210-4367.

For information related to working characteristics of created moissanite at the bench, call Mark Mann at (406) 961-4426 or (800) 210-4367, ext. 251.

Illustrations by Lainie Mann
©2003 Visual Communications

Copyright © 2002 by Bond Communications