Calcsilicate minerals

Overview

	Leucophoenicite (pinkish-violet), with willemite (green), and franklinite (black). Width 12 cm.

The 'calcsilicate' or calcium-silicate units occurred interlaminated with the ore units, inside the Zn-Mn-Fe orebodies at Franklin and Sterling Hill.

They formed tabular to highly irregular segregations and consisted chiefly of andradite, feldspar, hendricksite (a Zn mica) and calcite.

The calcium-silicate units also contained a much wider range of species than the ore units, and contained variable amounts of rhodonite, pyroxene, amphibole, vesuvianite and other minerals.

Since these minerals were regarded as "gangue" during mining operations, detailed records of their occurence and composition are sparse.

	Glaucochroite (light blue), leucophoenicite (pink), willemite (green), andradite (yellow-brown), franklinite (black). A classic specimen from the Franklin Ca-silicate units. Franklin, NJ. Width 8 cm.

	Rhodonite (pink) in bladed crystals, with barite (white). Large amounts of rhodonite were present in the Ca-silicate units, and some was recovered in euhedral crystals. Most of these are of blocky, rectangular habit. Some crystallized samples, such as this one, however, have a thin bladed habit. Franklin, NJ. Width 6 cm.

	Vesuvianite (blue), andradite garnet (yellow-brown), hendricksite mica (black). A colorful example of the bright blue "cyprine" variety of vesuvianite found in the Franklin mine. Franklin, NJ. Width 5 cm.

Some additional information on minerals of the Ca-silicate units is provided by species name (listed on the left). For further information, the viewer should consult Dunn (1995).

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