THE NONMETALLIG MINERALS. 

 2. MONAZITE. 



383 



Composition, a phosphate of cerium motals of the g-eneral formula 

 (Ce, La, Di) PO^. Actual aualyses as given by Dana yielded results 

 as below: 



Constituents. 



Phosphoric anhydride (P2O5) 



Cerium sesquioxlde (CeoO^) 



Lanthanum sesquioxide (LaoOa). 

 Didynium sesquioxide (DI2O3) . . . 



Yttrium sesquioxide (Y0O3) 



Iron sesquioxide ( FcoOa) 



Silica (SiOo) 



Thorina (ThOo) 



Lime (CaO) 



Ignition 



Total 



29.28 

 31.38 



30.88 



II. 



1.40 

 6.49 



99.63 



27. 55 

 29.20 



26. 26 



3.82 

 1.13 

 1.86 

 9.57 

 0.69 

 0.52 



100. 60 



I Burke County, North Carolina. 



IIArendal, Norway. 



The crystals are commonl}" minute, often flattened; not uncom- 

 monly in form of small cruciform twins. The mineral also occurs in 

 coarse masses yielding angular fragments. Hardness, 5 to 5.5; spe- 

 cific gravity, 4.9 to 5.3. Color, hyacinth-red to brown and yellowish, 

 subtransparent to translucent. 



Localities and mode of occurrence. — The common form of occurrence 

 of the mineral is that of minute crystals or crystalline granules dis- 

 seminated throughout the mass of gneissoid rocks. Owing to their 

 small size they have been very generally overlooked, and it is only 

 where, through the decomposition of the inclosing rock and the con- 

 centration of these and the accompanying heavy minerals — as magne- 

 tite, garnet, etc. — in the form of sand, that it becomes sufficiently 

 conspicuous to be evident. Prof. O. Derby was the first to point out 

 the widespread occurrence of the mineral as a rock constituent, he 

 having obtained it in numerous and hitherto unsuspected localities by 

 washing the debris from decomposed gneisses of Brazil. Although 

 widespread as a rock constituent and of interest from a mineralogical 

 and petrographical standpoint, only the localities mentioned below have 

 thus far yielded the mineral in commercial quantities. 



North Carolina. — The mineral is found in considerable quantities in 

 the form of small brown, greenish, or yellow-brown granules, often 

 rounded by water action, in the gold-bearing sands of Rutherford, 

 Polk, Alexander, Burke, and McDowell counties, and also in the neigh- 

 borhood of Crowders Mountain, Gaston County, and at Todds Branch, 

 in Mecklenburg County, where it occurs associated with zircons and 

 an occasional diamond. Fine crystals over an inch in length have been 

 found in Mitchell County, and large cleavable masses, sometimes 3 or 



