Contrary to some belief, Mother of Pearl is NOT poisonous. Several rumored cases cite Mother of Pearl as the cause of severe physical problems and even death. However, not one case has been documented or proven to be true. In nearly all of the cases I have heard, the complaining parties had many other serious health problems. Usually, preexisting asthma, emphysema or allergic reactions are the cause of any health problems associated with working with Mother of Pearl. Mother or Pearl is composed of 85% calcium carbonate, 12% conchiolin, and 3% water, none of which are harmful or poisonous. The possibility of an allergic reaction does exist, but normally isn't of serious consequence or life threatening. The typical symptoms that I have heard of are nausea, vomiting, headaches, coughing, and fever. For those who are allergic or have a reaction, these symptoms can persist for up to two days. I currently know personally of only 4 or 5 knife makers, of the 500 that buy Mother of Pearl from my company, who occasionally suffer from symptoms of this type. That puts the percentage of sufferers at about 1%. This is by no means a scientific figure, but it is simply to give you, the reader, an idea of your likelihood of becoming ill from this type of work.
There is some risk involved! Ground fragments of Mother of Pearl are the equivalent of tiny glass fragments. As you can imagine, these fragments are not good for your eyes, nose, throat, and especially your lungs. Breathing pearl dust, like any other dust, can cause build up in the lungs, cause difficulty breathing, and shortness of breath. So be smart and buy a good filtration mask and wear safety glasses, preferably air tight goggles so as to prevent dust from getting into your eyes. Knife makers should wear goggles and a mask regardless of what they are grinding.