Quartz, with a hardness of seven, exceeds the drilling capability of standard metal drill bits. Beyond dulling a metal drill bit rapidly, the heat generated by friction can crack the quartz crystal. To drill a hole in quartz, you need a drill bit that uses a material harder than quartz. Diamond-tipped drill bits use small pieces of diamonds, hardness of 10, bonded to a carbide arbor. Even with a diamond drill bit, you will need to reduce the friction at the contact point between the drill bit and the piece of quartz.
Things You'll Need
Leather work gloves
Diamond drill bit
Dip the clean rag in the cold water. Leave the rag dripping wet for the next step.
Wrap the quartz pendant with the dripping wet rag, leaving the area of the pendant where you need to drill the hole exposed.
Secure the rag-wrapped pendant in the table-mounted vise; make sure the exposed area of the quartz pendant is facing up.
Put on your safety glasses, leather work gloves and face shield.
Place the diamond drill bit in the mandrel of the rotary tool and place a second clean rag into the cold water.
Set the speed of the rotary tool mid-way and begin drilling into the quartz pendant. Keep the bit at a 90 degree angle to the pendant to produce a straight hole. Apply just enough pressure to let the rotary tool do its job.
Remove the clean rag from the cold water and squeeze the rag over the quartz pendant to cool the diamond drill bit. Continue drilling as you cool the stone and drill bit with the cold water.
Release the wet rag-wrapped quartz pendant from the table-mounted vise after you have completed the drilling process.
Dry the drilled quartz pendant with a clean rag to make the quartz pendant ready for hardware.
If you aren't sure how big you want the hole, start with a smaller bit. You can always make the hole bigger later, but you can never make it smaller.
Shards of quartz are sharp and can cause serious injury to your skin and eyes without proper protection.