Introduction to the mineral species

Overview

The minerals of the Franklin-Sterling Hill mining district include more than 340 species. 

	Hetaerolite crystals (dark orange) included within a zincite crystal (yellow). Thin section, plane polarized light.  Franklin, NJ. Width 0.2 mm.

Various groupings and classifications have been made for the myriad minerals found in the Franklin-Sterling district over nearly 190 years of scientific publication. 

For a good review see part II of Dunn (1995). For a discussion from the 1930s, see Palache On-Line.

These minerals have been placed into a variety of classifications over the many years that the deposits have been scientifically investigated.

For purposes of discussion, a highly simplified classification follows:

This Website focuses just on the minerals of the two unique Zn-Mn-Fe orebodies (yellow above).

The distinction of ore units and Ca-silicate units is that discussed in Frondel and Baum (1974). Minerals of "recrystallized" areas, or ascribed to hydrothermal alteration, as described in Frondel and Baum (1974), are here placed into a single "secondary minerals" sub-category.

Within the orebodies, species may be present in two or more such sub-categories. 

For example, willemite is present in primary ore, in (primary) calcsilicate assemblages, and as a secondary mineral in fracture and vein fillings crosscutting both ore and calcsilicate units.

	Franklin zinc ore. Franklinite (black), willemite (yellow-green), zincite (red), and tephroite (gray). Polished surface. Width 2 cm. Franklin, NJ.

Short discussions on the ore minerals, calcsilicate, and secondary minerals from the two Zn-Mn-Fe orebodies appear here. 

For further information the viewer is referred to Dunn (1995).

[to TOP of page]