96 



C. U. Shepard on New Mineral Species. 



Art. X. — Five New Mineral Species; by Professor 

 Charles U. Shepard. 



1. Xanthitane. 



In hollow crystals with the form of sphene, and pulverulent. 

 Color pale yellowish white, resembling some varieties of sulphur 

 or of decomposing wulfenite. Lustre generally feeble, but in some 

 instances bright and resinous. Brittle. Hardness =3-5. G. =2-7 

 to 3*0. Cleavage indistinct. Heated in a glass tube emits mois- 

 ture ; and before the blowpipe, has all the reactions of titanic acid. 

 It contains 12 5 p. c. of water, and consists of titanic acid with 

 traces of zirconia. It is found in a decomposing feldspar, asso- 

 ciated with zircons, at Green River, Henderson Co., N. C. ; and 

 probably proceeds from the decomposition of sphene. 



2. Pyromelane. 



Found in crystalline grains of the size of kernels of Indian 

 corn (and rather larger), in the gold washings of McDonald 

 County, N. C. The grains are irregular and much pitted, some- 

 what like those of chondrodite. Hardness =6 5. G. =3-87. Color 

 dull red brown to nearly black, rarely with patches of yellow. 

 Translucent. Lustre resinous, to resino-vitreous. 



Before the blowpipe infusible, but turns black and becomes 

 opaque ; and hence the name, in distinction from pyrochlore, 

 which by heating, becomes green, or greenish yellow. It is solu- 

 ble in the fluxes, with the reaction of titanic acid and iron. It is 

 undecomposable with sulphuric acid, except in a slight degree ; 

 but yields to fusion with bisulphate of potash. It is essentially 

 a titanate of alumina and iron, with only traces of glucina? and 

 lime. It may also contain zirconia. It would seem to be exceed- 

 ingly scarce. 



Pyro-guanite minerals. 



The three following species occur at Mong's Island, one of a 

 group of five small islands, situated in the Caribbean sea, 30 miles 

 distant from the Musquito coast, in lat. 12° N, long. 71° W. 

 They were brought, as a sample of the so called petrified guano, 

 to Charleston, S. C, in the bark Jane Dolen, Capt. A. F. Winslow, 

 in a recent voyage to Porto Cabello. Captain W. informs me, 

 that the island where it occurs, has an area of about two hundred 

 acres ; and that the formations are coralline, tertiary rocks and 

 trap, which rise into hills, four hundred feet above the level of 

 the sea. The petrified guano incrusts nearly the whole island, 

 to the depth of many inches. In general character, it is hard 

 and stoney ; of a cream color when exposed to the weather, and 

 yellowish brown, within. It is totally destitute of ammonia, 



