1892.] Mineralogy and Petrography. 613 
peridotite in the Portage sandstones near Ithaca, N. Y. In a horn- 
blende-andesite inclusion in the Capucin trachyte Lacroix’ finds one 
cavity containing magnetite, biotite, fayalite and hypersthene—a dif- 
ferent association of minerals from that in any other cavity. The 
most interesting of these minerals is the fayalite, which occurs in tiny 
crystals with a golden yellow color, due to a ferruginous pigment. 
Mineralogical News.—A series of new analyses of amarantite 
from the Mina de la Campania, near Sierra Corda, Chile, give: SO, = 
35.46; Fe,O, = 37.46; K,O = 11; .Na,O = 59; HO = 28.29, 
corresponding to Fe, 8,0, + 7H,O. The mineral has a specific grav- 
ity of 2.286, and at 110° it loses three molecules of water. Its axial 
ratio as ag by Penfield’ is a : 6: ¢ = .7692: 1 : .5738 with 
a == 95° 38’ 16”; p = 90° 23’ 42”,7 = 97° 13’ 4”, and 2Ena = 
63° 3’. ti ssctions parallel to the trachy-pinacoid the extinction is 
16°-17° in acute £. Sideronatrite from the same place occurs in fine 
orange or straw-yellow fibres, with orthorhombic symmetry (not mon- 
oclinic as Raimondi asserts). Its density is 2.355. A mean of sev- 
eral analyses yielded : 
SO, FeO, NaO H,O 
44.22 21.77 16.39 arose, SO, Fe, 8,0, + 7H,0. 
The mineral suffers a loss of four molecules of water at 110°. Asso- 
ciated with sideronatrite are little white masses composed of a sub- 
stance with hexagonal optical properties. It is positive with o — 
1.558, « = 1.613 for doo light. Its density — 2.547-2.578, and its 
composition is: H,O = 11.89; SO, = 51.30; Fe O, = 17.30: tet 
= 19,68 + KO == cas T6, corresponding to 3Na, SO,, Fe,(SO,), + 
6H,0. With these analyses are also given those of a pieropharmaco- 
lite from Joplin, Mo., of pitticite from the Clarissa Mine, Utah, of 
gibbsite from Chester Co., Pa., and of atacamite from Chile. The 
analysis of the first mentioned mineral leads to the formula (H, Ca 
Mg), As, O, + 6H,O. The pitticite gave: H,O = 17.64; As,O, = 
39.65; Fe,O, = 33.89 = 4Fe,(As O,),. Fe(OH), + 20H,O. The 
mineral is not a mixture of the sulphate and arsenate of iron as is the 
German variety. No definite conclusion was reached as to the compo- 
sition of the gibbsite other than that it is a hydrous aluminum phos- 
phate.——Though columbite has been known to exist in the Black 
1Bull. Soc. Franc., d. Min., xiv, p. 10. 
2Zeits. f. Kryst., xviii, p. 585. 
