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Jewelry, Gems, & Minerals/Drilling a hole into gemstones(topaz,Tourmaline,etc)

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Question
Hello,

I bought a strand of topaz (faceted heart  briolette 7mm) to make wire wrapped earrings with gold filled wire (24 gage, half hard round), but  the pre-drilled hole on the topaz was so small that I couldn't put the wire thru.

So to make the hole bigger, I bought a manual mini drill bit set (gage sizes 61-80) and the 2nd smallest drill bit fit into the hole but ended up breaking the stone...

It is 7mm and a tiny stone, but what's the best way to make the hole bigger? should I try  an electric drill?

I would appreciate any input you have.

Thank you so much!!

Sincerely,

Seunghu

Answer
Dear Seunghu,

The tool to use and avoid breaking the gemstone bead is a Diamond Coated Drill Bit, such as the one on the left side on the following web page:
http://www.riogrande.com/Search/diamond-bits

Steel drills are not hard enough to cut topaz and you ruin both the drill and the stone!

To use the tool safely without stone damage requires a rotary hand tool such as a variable speed Dremel™ electric hand piece. These are like a small drill motor but more precise variable speed offers the fine control needed to open the holes without burning the drill bit or overheating the gemstone. Home supply, hobby, hardware and similar stores sell these tools. If the tool is of good quality, you may select from several different brands including Dremel™.

The secret to doing a good job is to use a drill bit or diamond reamer small enough to go into the hole without pressure (for reamer) and to just barely begin to enter the hole if using a drill bit.  Keep the bit wet with water to clear debris and prevent heat which will crack a stone. If hand held, keep a wet tissue or small wet sponge in the same fingers or water nearby to regularly dip the gem while drilling. Drill at a slow speed to begin and you will gain a feel for a speed appropriate for the gem being worked.  Drill a slight amount, remove the bit to allow debris to clear and rewet the drill and the hole.  Drill from both sides if possible to prevent breakout on the back side of gem when drill bit emerges.

Heat and pressure cause the most damage in drilling gemstones. Prevent heat with water and use gentle pressure. Do NOT allow a reamer or bit to angle into the hole since it might bind and break the bit or the gemstone. A tapered reamer may be moved around in the hole to enlarge it but use care that the tool does not bind without warning in the hole.

A small mound of modeling clay with a recess for water and just enough room for you to hold the stone in place will facilitate holding the gem and maintaining a cool working situation.  Needless to say, you must use a very steady hold on the hand piece to keep the diamond tool running true with the small original hole in the gem bead.

Thanks for the question...a good result comes from using the right tool and a gentle approach.

God Bless and Peace. Best wishes with the project.
Seunghu, feel free to use a follow-up question if you need more explanation.  Thomas.  

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Thomas

Expertise

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.

Experience

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/Credentials
Education is English/Physics! Started in human resources, to advertising, to jewelry...wow, 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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