Muscovite

One specimen in the Hancock collection was identified as muscovite by optical tests. It consists of irregular flakes of greenish-white mica embedded in limestone and was found in the Furnace quarry at Franklin.

Muscovite has also been noted as a more or less common constituent of the pegmatites.

Barium muscovite
A massive pink mineral with obscure cleavage, intermixed with microcline, garnet, manganophyllite, and franklinite, proved under the microscope to have the optical properties of muscovite. A purified sample was analyzed by Bauer (282) with the results shown below.

**Analysis of barium muscovite**
SiO₂	41.37
Al₂O₃	32.64
MnO	0.62
CaO	0.36
MgO	1.55
ZnO	1.84
BaO	9.89
K₂O	6.33
Na₂O	1.51
H₂O	4.05
	100.16

This analysis, together with the optical properties, seems to establish this mineral as a barium muscovite, practically identical with the substance to which the variety name "oellacherite" was given by Dana.


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	This page created: August 12, 2006 6:40 PM