Hi Noel,
You give me too much credit, but I’ll try to help. Grinding pearls
and MoP should be done wet. That will keep dust down and protect the
pearl/MoP from heat. The dust is not good to breath - the same is
true of any dust, but pearl dust has some hard,sharp, very small
fragments that are hard for the lung to expell. It’s not gonna kill
you, but breathing it will make you cough and ongoing exposure will
damage the lung. My favorite toxicologist says it is a physical
irritant, and causes essentially silicosis. I’m not a lapidary, but
I understand virtually all stones are cut and ground under wet
conditions anyway.
Cuttlebone is not quite the same. It's softer like chalk, and not
so irritating. I cut mine with a jeweler’s saw blade, and see
little dust - more like fine crumbles. However, I’ve only cast
little ingots, so I didn’t do any carving of the bone that would
generate dust. You probably make a form by pressing into the
cuttlebone, and then brushing away the loose dust. I’d still avoid
breathing the dust. A dust mask should do the trick since you’re
not doing any high speed cutting or drilling. Cuttlebone cutting is
messy enough that maybe your class could do that part outside. You
probably knew there was a 2-part article in Lapidary Journal a few
years ago that went over cuttlebone casting.
Have a great one, Judy