314 DESCRIPTIONS OF MINERALS. 
For other analyses of hydromica slates, see Dr. Genth’s report on 
the Mineralogy of Pennsylvania ; also Geological Report of F. Prime, 
-Jr., for 1874, p. 12. 
Parophite. The material of a schist or slate—Parophite Schist— 
which cuts like massive talc, is of greenish, yellowish, reddish, and 
grayish colors, and is probably a damourite or hydromica slate, with 
some free silica (quartz). An analysis afforded Silica 48-46, alumina 
27°55, iron protoxide 5°(8, magnesia 2°02, lime 2:05, soda 2°35, potash 
5°16, water 714=—99°81. It is from Pownal, Vt., and St. Nicholas, 
Stanstead, and other neighboring parts of Canada. 
Sericite. A damourite-like mineral, with the pearly lustre of tale, 
and the composition of a hydrous mica; it is the basis of a glossy 
schist ; near Wiesbaden. ‘The scales are described by Resernbusch as 
appearing fibrous when highly magnified. Analysis afforded Silica 
49-00, alumina 23°65, iron protoxide 8:07, magnesia 0:94, lime 0°63, 
soda 1°75, potash 9°11, water 3°47, titanic dioxide 1°89, silicon fluoride ~ 
1-40=100°14. 
Paragonite. A hydrous mica containing soda in place of potash. 
From Mount Campione, in the region of St. Gothard. Color whitish, 
grayish, yellowish, greenish. Analysis afforded Silica 46°81, alu- 
mina 40°06, magnesia 0°65, lime 1:26, soda 6°40, potash trace, water 
4°82—100. Pregrattite. from the Tyrol, affcrded soda 7:06, potash 
1°71, water 5°04; it exfoliates like the Vermiculites. Cossaite is here 
included. 
Groppite. A rose-red to brownish-red foliated mineral from Gropp- 
torp, Sweden. 
Huphyllite. Mica-like, with folia rather brittle, pearly lustre, 
white or colorless. Contains much scdium. An analysis afforded 
Silica 41°6, alumina 42°38, lime 1°5, potash 3°2, soda 5:9, water 55=100. 
Occurs with corundum at Unionville, Delaware County, Pa. 
Gillacherite. Mica-like ; strong pearly in lustre, grayish white to 
white ; clastic. Analysis obtained 7°61 potash, 1°42 soda, 4°65 baryta, 
and 4°43 water, besides silica, alumina, ete. 
Cookeitc. In minute mica-like seales, and in slender six-sided 
prisms. Affcrds only 2°57 of potash, with 2°82 of lithia ; the water 
18°41 per cent. Occurs on crystals of red tourmaline at Hebron and 
Paris, Me., and has proceeded from its alteration. Named after Prof. 
J. P. Cooke, of Cambridge, Mass. 
Voigtite is the mica of a granite at Ehrenberg, near IImenau, which 
has the composition of biotite, plus 9 to 10 per cent. of water. 
Roscoelite. A vanadium-mica, of dark brownish-green color, occur- 
ring in micaceous scales, and affording over 20 per cent. of vanadium 
oxides, along with 47:69 of silica, 14:10 cf alumina, 7°59 of potash, 
4-96 of water, and a little magnesia and soda. From Granite Creek 
Gold Mine, El Dorado County, California. 
F’ahlunite. 
In six and twelve-sided prisms, usually fohated, parallel 
to the base, but owing its prismatic forms to the mineral 
from which it was derived. Folia soft and brittle, of-a 
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