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Jewelry, Gems, & Minerals/Black Onyx and hear


How well does a commercial grade black onyx take heat?  The ring repair is at the top of the shank just below the carriage. 14K white gold mounting.

Dear Karin,

You best be prepared to replace the onyx if anything goes even slightly wrong.  Onyx can be damaged sometimes by a burnt look and light "bleached" areas and once in a while simply cracked. Either way the stone is ruined.  I know jewelers who routinely size gold rings with onyx without removing the stone and they get away with it when the shank is light and the solder joint is not so close to the stone. Sizing is the least concern for heat damage since the stone may be immersed in water, etc. for the sizing work. When the heat must be close to the stone as in your case,I would remove the stone to do the work or in the least pack the stone and around it with some kind of heat shield material.  You still must leave enough metal exposed to get heat properly on both sides of the joint, use a quick hot flame and not accidentally melt any of the carriage.

If the gem in in a difficult setting style for removal and resetting, it is your call if heat shield material may be packed close enough to protect the stone and allow proper soldering. If there is any doubt, remove the stone.  With onyx, sometimes it is easier to allow the stone to be destroyed and then replace it than to try and peel back a bezel, etc., while the stone is set. Generally, I will advise the customer that the stone may be damaged and will be replaced. There must be an added charge, of course. (Be certain the size and dimension of stone is readily available prior to proceeding.)

The gems are somewhat unpredictable in heat tolerance.

Karin, I wish you shining success in getting this job done.  God Bless, Peace.  Thomas.

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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.

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