MINERALOGY. 557 



eiice of 7 per cent, niaugauesc protoxide, which is the only distingiiisli- 

 iiiji' feature of the variety. {Geol. Soc. Belg., 1884.) 



Sijnadc'phite. — A new arsenate of manganese from Nordmark, Swe 

 den, described hy II. Sjogren. It occurs sometimes with scheelite, some- 

 times in cavities in the i)orous calcium carbonate. The crystals belong 

 to the monoclinic system, and are very near liroconite in angle; also 

 not far olf from laznlite. The color is blackish-brown to black, being 

 considerably darker than that of the other manganese arsenates de- 

 scribed from the same locality; it is translucent to nearly opaque. The 

 luster is vitreous on the fracture, submetallic on crystalline faces. The 

 hardness is 4.5, the specific gravity 3.40 to 3.50. The composition is 

 stated to be that of a hydrated arsenate of manganese, with also alumina 

 and iron, being near that of diadelphite, from which, however, it differs 

 in containing less water. The crystalline forms of the two species are 

 also distinct. The name has reference to the close relation to diadel- 

 phite and the other allied species from the locality. {Oeol. For. Fiirh., 

 iStockholm, vii, 235, 382, 407.) 



Utahite. — A mineral from the Eureka Hill mine, in the Tintic district, 

 Utah, described by Arzruui. It occurs in fine scales forming an aggre- 

 gate with silky luster as a coating on quartz. Under the microscope 

 the scales are found to be hexagonal plates with rhombohedral planes on 

 the edges. ]S"otwithstauding the minuteness of the crystals it was found 

 l)ossible to measure them, and so to determine the length of the vertical 

 axis, namely, c = 1.1389. The mineral has been analyzed by M. Damour 

 and shown to correspond with the formula 3 Fe^Oa, 3 SO3+4 H2O ; it is 

 consequently a basic sulphate of iron sesquioxide. {Zeitsch. Kryst., ix, 

 558; or Bull. Sog. Min. France, vii, 126, 128.) 



Xanthoarsenitc. — Described by Igelstrom as a new arsenate of man- 

 ganese from the Sjo mines in the parish of Grythyttan, Sweden. It 

 occurs in sulphur-yellow masses, resembling the yellow compact garnet 

 found with rhodonite at the L<\ngban mines. It is associated with haus- 

 mannite, magnetite, and hen)atite. Ko crystals were found, but Ber- 

 trand has shown that it is optically biaxial; whether it belongs to the 

 orthorhombic, monoclinic, or triclinic system could not be decided. An 

 analysis showed it to be a hydrous arsenate of manganese chiefly, with 

 also a little antimony replacing the arsenic, and small quantities of iron, 

 magnesium, and calcium replacing the manganese. It is very near the 

 chondroarsenite of the same author, only differing in containing a little 

 more water, and having a more de(;idedly yellow- color; it is also related 

 to the manganese arsenates from Nordmark described above. {Bull. t<oc. 

 Mill., VII, 237.) 



Zunyite. — A remarkable new mineral described by Hillebrand Irom 

 the Zuiii mine on Anvil Mountain, near Silverton, San Juan County, 

 Colorado. It occurs intimately intermingled with the suli)hide of ar- 

 senic and lead, guitermanite (see above), from whi(*h it was separated 

 for examination ]>y removing the sulpnide by nitric ;t<;iu. The crystals 



