Small Holes & Hard Rocks

So you want to drill a hole in a cabochon or other gemstone? Drilling gemstones has to be one of the most challenging and potentially frustrating lapidary techniques to master. The holes are usually small, the stone is harder than expected, diamond burrs wear out or break and it always requires more time than planned. Plus, there is always the problem of the gemstone chipping around the hole. Or even worse, the stone becomes a pile of worthless and sometimes very expensive fragments.


Sandy Craig at Orca Gems developed the following method. Admittingly, stone drilling is still an intimidating process, yet I've had a lot of luck with this method.


Get a plastic bowl, a piece of 1"x4" wood and a nail the same diameter as the drill.


Drill a hole in the 1"x4" the same diameter as the nail.


Insert the nail through the board and into the bottom of the plastic bowl. Epoxy everything in place and to seal up the hole in the bottom of the bowl.


Clip off the nail at about 2-3 mm.

Drill the first hole to a depth equal to the length of the nail or half the total speth of the hole.

Now clamp the board and entire drill in place so that the nail is centered directly under the drill.

If done properly, the nail will hold the cab in place. Drill the second portion of the hole.

No chipping. No blow-out. No mess. Just a nice little hole.

Add a pinch bail to complete the project. (This cab still needs to be polished. So a little water was added to show what is will look like when finished.)

If the hole is off-center, use a bead reamer to straighten it out. This method works great for stones up to a hardness of maybe six and for drilling side-to-side and front-to back. The maximum depth is about .375" to maybe .5".

If you need to drill something harder or deeper, then it's probably better to get something like this drill.

Can't afford a $1800 tool to put some holes in rocks? Here's a gemstone drilling service. An average hole will run somewhere between $8 to $15 depending on the diameter and depth. The minimum order is $150. The holes from an ultrasonic drill are usually cleaner and don't require polishing. 

If drilling gets into to your blood, you can try to go crazy like Craigor Clark does at Slice of the Universe. 

Minnesota Lapidary Supply sells a few accessories for drilling that look very useful.

One additional tip.

If you need to core drill a stone, glue a thin piece of wood to the back of the stone. This will normally stop any blow out when the drill finishes the hole. Someone also mentioned using cardboard instead of wood.

Good luck!

Tucson 2012: "Survivor" Meets "Treasure Hunt"

Compared to last year, Tucson 2012 was a pretty mellow, uneventful yet productive show for Bright Star. No record cold temperatures. No endless wind storms. However, the more gem and mineral shows I attend, the more I'm convinced the gem business is really a cross between "Survivor" and "Treasure Hunt". 


The "Survivor" portion occurs by trying to avoid the scams and not getting robbed. Unfortunately, an Oregon sunstone miner had their entire inventory stolen a few days after the GJX show. This was reportedly only $800,000-$900,000 in loose stones and finished jewelry. The International School of Gemology is offering a $1,000 reward for the recovery of these gemstones, etc. More details can be found here.


"Treasure Hunt" occurs during the endless search for good rough rock. A second and again unfortunate reality is Tucson 2012 really didn't produce any significant new discoveries. There were plenty of dealers content to offer the same types of rough. Of course there was a plentiful supply of some of the more popular agates and jaspers but there really wasn't that much new material available.

Two really neat materials that I overlooked last year are the Utah Lace Opal and Atlantasite. 

Lace Opal slightly resembles crazy Lace Agate and is offered in every form imaginable -rough, slabs and finished cabs and jewelry. Bright yellow to orange patterns run through a bright red to crimson background. Aspen Rock and Gem are both the direct miners and distributors. Call Larry or Joyce at 970-250-0178 or 970-250-4094 to try some.

Atlantasite is found only on the island of Tasmania. The miners really must have a sense of humor to name a stone after an ocean on the other side of the world. Purple Stichtite provides a nice contrast to the almost chartreuse yellow or green Serpentine. 

While both of these materials require treatment with some type of polymer to help stabilize them, the results are worth it. The finished cabs are really stunning. 

Need a knife? Need a really nice, custom one-of-a-kind with stone inlay handles knife? Knives were one of the "in" items this year.

Custom knife maker Steve Nolte of Nolte Knives is the guy to see when you want the best in one-of-a-kind cutlery. This was Steve's second year exhibiting in Tucson and he seemed to really enjoy himself. His specialty is using Damascus steel combined with different stones including Turquoise, Agates, Jaspers and even the above mentioned Lace Opal to create the ultimate cutting tools. 

All the knives are sold with a custom leather sheath that often compliments and reflects upon the style of the knife. Steve can be reached through his website http://www.snolteknives.com .

Hopefully, this marks the beginning of regular postings to the Bright Star blog. Sometimes it's a little surprising where all the time goes - 2011 was certainly one of those years.