Anthracite coal carving

I was recently given many chunks of anthracite coal and asked to make
custom carved jewelry from them. I’ve never worked with the stuff
before and I’m not a lapidary artist. What tools are best for this
material? I would very much prefer to not ruin my goldsmithing bench
tools. Does anyone have anthracite carving experience?

Alexis Romeo in the rolling hills of Corning, NY

as with anything no do not use your gold smithing tools use a set
specifically for this task. I would think dentists rasps and tools
used for plaster carving would be best.

Your local sculptor and cameo carver Teri

Hello Alexis, anthracite does not necessarily mean jet. The material
your are using may or may not be something that is carving quality.
Good quality jet is uniform and has very little grain (hard and soft
spots, fractures, etc.). Anthracite may be infused with other
minerals that are much harder then jet. Used as a burning material
that may be okay, but for carving it can be more than it is worth to
try and work.

If on the other hand you have pieces that seem to be fracture free,
or at least able to break at the fractures and still leave you a
piece large enough to carve what you would like, and not full of
little hard or soft spots, it is a delight. It makes a complete mess
while you work it. Unless you are careful you will have black dust
that clings to everything, on everything. It is soft enough that many
woodworking tools and metalworking tools will suffice, needing no
lapidary specialties. You can saw it with a hacksaw, and file it with
even a fine rasp. Sanding can be done with regular sandpaper, and
finished with wet/dry fine grits. The sandpaper loads up super
quickly, but the bits you use in you rotary tool can easily carve
smooth enough to remove material quickly and leave very little
sanding to be done. Any metalworking bit will work (pretty much), but
carbide bits work best and are not dulled or ruined for jewelry work.
I have even used a pocket knife to leave a hand carved look, and then
simply used Tripoli to polish, and Zam to finish. The material has a
very friendly feel, and a good piece works like plastic. It seems
most of the industry in the states uses it for inlay. It glues well
and is very light. I am sure if you Google jet, you will find an
abundance of info and pics of current jewelry being made. Look out
for unscrupulous vendors, as there are many ways to plasticize the
dust, and apparently man made jet is commonplace. Thomas III