Silica, the earth’s most abundant mineral, is made up of oxygen and silicon. It is a part of many, many processes including mining, pottery making, glass making, and granite work including tombstone making. The lung disease caused by crystalline silica dust is called silicosis and has been known since the time of Hippocrates. It is an inflammatory disease.
In the fifties after many studies, it was learned that autoimmune diseases including rheumatoid arthritis could be caused by exposure to crystalline silica. The connection though proven is not well understood. Rheumatoid arthritis is also an inflammatory disease.