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Minerals recently investigated by M. Hermann. 11 
1en. If the uncombined silica bears any proportion to the in- 
ee ones the excess of this ingredient is sufficiently ex- 
4. Lepourre anp LinpsayIteE. 
The Lepolite of Hermann* is a feldspathic mineral from Fin- 
land, identical in chemical formula with anorthite, but differing 
in having its crystals oblique or inclined to the deft, (when the 
edge T': T’ is in front) instead of to the right. He gives for 
se A 120°30’, P:M 93°, which is the angle between two 
cleavage planes. H=6. G=2-75-2-77. Vitreous and transpa- 
rent; colorless, grayish, greenish, often brownish externally. 
Crystals often large, and sometimes two inches long. Composition 
Re Si+sa1 i 
Si Al #e Oa Mg Na loss by ignition. 
1. From Lojo, 4280 38512 150 1414 227 150 156=9969 
2. From Orrijervi, 42°50 33:11 400 400 587 169 150=9954 
_ It fuses with difficulty on the edges before the blowpipe, and 
is decomposed by concentrated acids. 
Hermann has also published a description of a new feldspar 
which he calls Lindsayitet in the same memoir with the Lep- 
olite. The following are its characters: 
Monoclinic or triclinic, 'T’ : T’=120°, P on the axis 65°. Crys- 
tals often of large size. . = 4, G, = 2°83. Color, black ex- 
ternally, internally gray, bluish-gray, dull reddish. Subtranslu- 
cent. In a matrass yields water. Before the blowpipe fuses with 
difficulty on the edges. With the fluxes, the reaction of iron and 
Silica. Analysis afforded, 
Si Al Fe Fe Me K Na 
4222 9755 698 200 885 3:00 253 7-00 B trace =10013 
Oxygen ratio 21:90 12°84 209 044 349 050 064 6-22 
whence he deduces for the oxygen of the water, protoxyds, per- 
oxyds and silica, the ratio 1: 1:3: 4, and the formulat 
R? §i+3A1 5i+3H, 
which, excluding the water, represents the composition of anor- 
thite and also Hermann’s lepolite. 
Breithaupt, in volume xlvii, p. 236, of the Journal fir praktische 
Chemie, stated that the Lindsayite was properly a pseudomorph, 
after lepolite. ‘To this view Hermann objects in volume xlviii, 
254, (Nov. 1849,) mentioning that lepolite contains 10 to 15 per 
cent. of lime and lindsayite none. 
* Jour. f. i : Jour. f. prakt. Chem., xlvi, 396. 
t This ie Be ek dopeicicadld ; for the ger of ihe peroxyds and silica has 
more nearly the ratio 2:3 than 3:4. 
