COMPOUNDS OF CERIUM, YTTRIUM, LANTHANUM. 203 



Rogersite. A hydrous colmnbate of yttria, in whitish crusts, on 

 samarskite. From X. Carolina. 



Monazite. 



Monoclinic. In modified oblique rhombic prisms ; I A I 

 = 93° 10'. Perfect and brilliant basal cleavage. Observed 

 only in small imbedded crystals. 



Color brown, brownish red ; subtransparent to nearly 

 opaque. Lustre vitreous inclining to resinous. Brittle. 

 H.=5. G. =4-8-5-1. 



Composition. A phosphate containing cerium, lantha- 

 num, yttrium, didymium and thorium, with also a little 

 tin, manganese, and lime. B.B. it colors the flame green 

 when moistened with sulphuric acid and heated. Difficultly 

 soluble in acids. 



Biff. The brilliant easy transverse cleavage distinguishes 

 monazite from sphene. 



Obs. _ Occurs near Slatoust, Russia, In the United 

 States it is found in small brown crystals, disseminated 

 through a mica slate at Norwich, Conn. ; also at Chester, 

 Conn., and Yorktown, Westchester County, N". Y. 



Cryptolite. A cerium phosphate in minute prisms (apparently six- 

 sided), found with the apatite of Arendal, Norway. Color pale wine- 

 yellow. G.=4-6. 



ChurcJrite. A phosphate of cerium, didymium and. calcium ; from 

 Cornwall. 



Xenotime-. An yttrium phosphate having a yellowish-brown color, 

 pale brown streak, opaque, and resinous in lustre. Crystals square 

 prisms, with perfect lateral cleavage. H. =4-5. G. =4*6. Infusible 

 alone before the blowpipe ; insoluble in acids. From Lindesnaes, 

 Norway ; Ytterby, Sweden ; gold washings of Clarkesville, Ga., and 

 McDowell County, N. C. 



Parisite. Is a carbonate containing cerium, lanthanum, and didy- 

 mium, with fluorine. From New Granada. 



Lanthanitc. Occurs in thin minute tables or scales of whitish or 

 yellowish color, and is a hydrous lanthanum carbonate. From Bast- 

 nas, Sweden, and Saucon Valley in Lehigh County, Pa. 



Tengerite. An yttrium carbonate. Found in thin coatings at Yt- 

 terby, Sweden. 



Rhabdophane. A didymium and erbium phosphate ; from Corn- 

 wall, with sphalerite iblendei, which it resembles. 



Rutherfordite. A blackish-brown vitreo -resinous mineral. From 

 the gold mines of Rutherford County, N. C. 



Allanite, Gadolinite, Keilhauite, and Tscheffkirrite, are silicates con- 

 taining either cerium or yttrium. 



