The author of this note has repeatedly emphasized the important role of ferruginous chlorites in the composition of the ores of a number of tin deposits. However, as the practice of prospecting shows, the existing information is still clearly insufficient. At present, there are sufficient grounds to assert that ferruginous chlorites are specifically characteristic minerals for a large group of tin deposits belonging to the so-called. cassiterite-sulfide formation. For example, in almost all ore-bearing areas of the vast northeastern metallogenic province we now know representatives of the “chlorite” variety of cassiterite-sulfide deposits. Also increasing the value of chloritization as a prospecting feature is the fact that chlorite-rich deposits are almost certainly some of the highest quality tin concentrations, both in terms of reserves and ore content. In any case, the percentage of industrially interesting objects in this group is very high. Thus, although ferruginous chlorites are not a monopoly on tin deposits, their value as a prospecting feature for tin ores remains almost in full force.
