1890.] Mineralogy and Petrography. 363 
knoxvillite. A brick-red sulphide of antimony from the filling 
of a vein in a sinter deposit in the Steamboat Springs District, 
near the Comstock Lode, Nevada, is named mefastibnite by the 
same author. JVapalite™ is a dark reddish-brown substance of the 
consistency of shoemaker’s wax occurring at the Phoenix Quicksilver 
ine, Pope Valley, California, Its hardness is 2, and specific gravity 
1.02. It is brittle. It fuses at 42°— 46°, and boils at 300°. When 
first taken from the ground it is green by reflected light, and 
garnet by transmitted light. Upon exposure it loses its green fluor- 
escence. The composition of the mineral is supposed to be near C,H,. 
Nesquehonite is an alteration product of /ansfordite, the new mag- 
nesium compound described by Genth™ a few monthsago. The latter 
mineral, upon exposure, rapidly changes over into prismatic, ortho- 
rhombic crystals, usually arranged in radiating groups. Their axial 
ratio is a:5:c=.645:1:.4568. oP is the plane of the optical 
axes. The brachy-axis is the acute bisectrix, which is negative. The 
optical angle 2Vna==53° 5’. Hardness = 2.5, and Sp. Gr.= 1.83. 
The composition of the substance corresponds to MgCO,+3H,0 
[CO, = 30.22; MgO = 29.22, H,O = 40.32]. Artificial nesquehon- 
ite has been prepared by allowing aqueous solutions of magnesium 
carbonate containing carbon dioxide to stand undisturbed for some 
time. The crystals thus obtained present the same features as the 
natural product. Measurements of the indices of refraction on one of 
these crystals gave: a= 1.495, P = 1.501, y = 1.526. Perfect pseudo- 
morphs of nesquehonite after lansfordite (incrustations and stalactites) 
were fourd at the locality from which the latter mineral has been de- 
scribed—Lansford, Schuylkill Co., Pa-——WVatrophilite is anew member 
of the triphylite group lately described by Messrs. Brush and Dana * 
from Branchville, Connecticut. The mineral is usually found in 
masses with a good cleavage, although occasionally grains with an in- 
distinct crystal form are detected. It resembles very closely the lithi- 
ophilite (LiMnPO,) discovered by the same authors some time ago, in 
both its morphological and optical aspects. Its color, however, is a 
:deep wine, resembling the tint of Brazilian topaz. Its most character- 
istic features are its very brilliant lustre and its easy alteration into a 
a pale yellow, silky, fibrous substance that covers all its surfaces and 

12 Becker: Ib., p. 372. Š 
13 Genth and Penfield: Amer. Jour. Sci., Feb., 1890, p. 121. 
14 AMERICAN NATURALIST, April, 1889, p. 261. 
15 Amer. Jour. Sci., March, 1890, p. 205. 
