314 



REPORT OF NATIONAL MUSEUM, 1890. 



A coarse deep red granite is the most abundant, and is cut by numer- 

 ous extensive veins of quartz and feldspar which carry the gadolinite, 

 in pockety masses, and the other minerals mentioned. Most of the 

 mineral thus far found is altered into the brown-red waxy material 

 noted above and occurs in the form of masses weighing half a pound 

 and upward. One "huge pointed mass, in reality a crystal, weighed 

 fully 00 pounds; " another 42 pounds. One of the earliest opened 

 pockets yielded some 500 kilos (227 pounds) of the mineral. 



Of the foreign localities those of Kararfvet, Broddbo and Finbo, 

 near Falun, Sweden, and at Ytterby, near Stockholm (Specimen No. 

 62793, U.S.N.M.), are important, the mineral here occurring in the 

 form of rounded masses embedded in a coarse granite. On the island 

 of Hittero, in the Flecke tiord, southern Norway, crystals sometimes 

 four inches across have been obtained. 



Uses. — See under monazite, p. 383. 



10. Cerite. 



This is a silicate of the metals of the cerium group; of a com- 

 plex and doubtful formuhi. The analyses below, taken from Dana's 

 System of Mineralogy, will serve to show the varying character of 

 the mineral. 



Constituents. 



Silica (SiOo) 



Cerium oxide (CcoOs) ... 

 Didynium oxide (DioOa). 



Lanthanum (La-^Os) 



Iron oxide (FeO) 



Alumina ( AI.1O3) 



Lime (CaO) 



Water (HoO) 



19.18 

 64. 55 



7.28 



1.54 



1.35 

 5.71 



22. 79 

 24.06 



35.37 



3.92 

 1.26 

 4.35 

 3.44 



III. 



18.18 

 33.25 



34.60 



3.18 



1.69 

 5.18 



The mineral occurs in gneiss and mica schist, and is of a prevailing 

 pink to gray color. Specimen No. 62794, U.S.N.M., from Bastniiss, 

 Westmanland, Sweden, is characteristic, 



Uxes. — See under monazite, p. 383. 



11. Rhodonite. 



This is a metasilicate of manganese of the formula iMnSiOg,^ Silica 

 45.9 per cent; manganese protoxide 54.1. As a rule, iron, calcium, or 

 zinc replaces a part of the manganese. The prevailing form of the 

 mineral when in crystals is that of rough, tabular, or elongated prisms 

 with rounded edges (Specimen No. 83927, U.S.N.M., from Franklin, 

 New Jerse}^). It is also common in massive highly cleavable forms, and 

 in disseminated granules (Specimens Nos. 83927 and 83929, U.S.N.M.). 

 Rarely, as in the Ekaterinburg district of Russia, it occurs in massive 



