Benjamin, calaverite contains Au Ag Te2 along with other elements that can be running with the ore. The Te being tellurium and Te is in most cases mildly toxic. The fumes of Te can cause dry mouth, drowsiness, metal taste, headache, nausea, and garlic odor of the breath. Ingestion can cause abdominal pain, constipation, and vomiting.
I have yet to find a one stop source for info when looking for answers on refining that come to mind and that is why I have several books on the subject. Another good tool is this site for toxic info of elements. www.lenntech.com/periodic/elements/te.htm
Hope this helps to point you in the right and safe direction. Ron