Jewelry, Gems, & Minerals/Synthetic Gem


Hello, Thomas

This time I would like to ask about the synthetic gem:

1. Is there any differences between synthetic gem created by using hydrothermal or flame-fusion after it is polished ?

2. In order to have the same understanding of shape, I use the example of diamond that has Crown Height and Pavilion Depth. (I take the terminology from :

My question is : if I want to stick a synthetic ruby in the shape of the Crown Height (flat bottom) only on a flat surface, what should I do to have darker color ?

3. Which one is better in appearances given the same Crown Height shape and size : the hydrothermal ruby or fire-fusion ruby ?


Dear Donny,

The differences in the synthetic ruby made by flame fusion and hydrothermal methods is not normally apparent to the naked eye.  Some internal structures are different, revealing the method of growth of the crystal. This article helps in that regard but is honestly of little concern when answering your questions about appearance.

The flame fusion stones are generally much less costly and the color is the same. Sometimes the flame grown rubies are cut from the side of the boule (formation of ruby in a rod from the flame process).  Cutting from the side will allow larger stones to be cut but from that direction the gems are lighter in color and not as red as stones cut from the length( end to end) of the ruby rod.

A flat based stone is going to lack any internal reflection to emphasize color and the shallow depth will also make for a stone much less rich in color.  To make the stone darker means backing the setting with a dark substance.  The lively flash of the gem will not be apparent and will come from reflections of surface facets and not from internal reflection of light in the gem.

One method of growing the synthetic gems does not assure a darker finished stone. The color show has to do with depth of color to begin with in the rough material, with size and depth of the cut stone and the pattern of the cut.  You will have better color if some method is there to add a fully cut synthetic stone, with a pavilion, such as a round brilliant shape. The flat base(rose cut) will do little to show good color by itself.

Donny, I do hope this helps. Save money and get the flame fusion stone since color difference is not significant.

God's Blessings and Peace to All.  Thomas.  

Jewelry, Gems, & Minerals

All Answers

Answers by Expert:

Ask Experts




Have a question about jewelry repair or working with precious metal jewelry and gemstones? For many years up to December 31, 2010, I was a working professional bench jeweler, involved everyday with setting stones in mountings, designing and making jewelry, repairing and limited custom manufacture. If you work with jewelry as a hobby or as a profession, I might be able to help. I deal with the retail business, not mass production. Ask privately if you wish. See the box for that: It keeps your question between us. Please DO NOT ask MAKER'S MARKS, but metal quality marks are fine to ask. Please DO NOT ask diamond prices. See a gemologist for that.


I have extensive experience in design, service and making of jewelry. I deal mostly with precious metals and gemstones but work with many materials as needed and usable to create an artistic design. My experience also includes freelance photography and photographer of jewelry and similar items for a former employer and individuals. Design of custom items requires reading the desires of the client and being clear on what can be done within that framework...then fulfilling the transition of idea to reality. Effective communications is essential in a working designer/producer and customer relationship.

Education is English/Physics! Started in human resources, to advertising, to, what a road. I have had formal training in jewelry work and many shared experiences with top grade jewelers. We just never know were we will go or be. Follow your best, your dreams, with some discretion! Don't let the work tear up your body along the way as it has mine.

©2017 All rights reserved.