Tremolite and Actinolite

Tremolite is found rarely as simple isolated gray or white crystals in the limestone wall rock of both ore bodies. It is common in the form of asbestos, the white or pinkish fibers being mixed with calcite in stiff columnar masses that form a transverse filling of secondary veins. Such material is often found in collections mistakenly labeled sussexite, which it much resembles.

Koenig's analyses show that the fibers are of variable composition, but samples tested by the author showed no trace of iron or manganese and are certainly true tremolite.

In many references to supposed tremolite from the district the mineral is doubtless edenite (see page 72); also a part of the diopside and sahlite of earlier lists was probably edenite, though a part of it may have been tremolite.

A pseudomorph of tremolite, probably after diopside, is described on page 62.

**Analyses of tremolite**
(G. A. Koenig (132), analyst)
	1	2
SiO₂	55.84	53.50
Al₂O₃		1.36
Fe₂O₃		8.12
FeO	2.40	4.68
MgO	19.58	14.58
CaO	10.00	6.62
MnO	4.79	1.70
ZnO	4.59	7.10
H₂O	3.20	3.34
	100.40	101.00

Both samples had been treated with hydrochloric acid to remove calcite. The molecular ratio of silica to total bases approximates 1 to 1, and the material is tremolite containing considerable manganese and zinc.

Typical fibrous actinolite was seen in veins in the limestone of the Buckwheat mine in the stripping between the two legs of the ore body. It wits also found with magnetite in the Gooseberry iron mine.

It is, however, rare in the area, and the name as used in earlier lists applies, according to Mr. Canfield, to stout gray crystals of an amphibole that is probably edenite.


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	This page created: August 12, 2006 7:19 PM