Galena is a natural mineral form of lead sulfide. It is the most important lead ore mineral. One of the earliest uses was as kohl (cosmetic), which in ancient Egypt, was applied around the eyes to reduce the glare of the desert sun and to repel flies, which were a potential source of disease.
Calcite is a carbonate mineral and is transparent to opaque. Calcite, like most carbonates, will dissolve with most forms of acid.