74 
Monazite and Monazite Mining 
[. November 
It is possible that in some cases the monazite in pegmatized 
gneiss is formed by the gathering together of the proper elements 
disseminated through the original rock during recrystallization. 
It is probable that pegmatization in which much quartz with but 
little feldspar has formed represents a phase of recrystallization 
in which the quartz may either in part or wholly have come from 
the original rock itself or may have been added by solutions pass- 
ing through the formations. In either case the materials do not 
represent the work of active magmatic solutions or magmas such 
as might give rise to regular pegmatite bodies. In those recrystal- 
lized or pegmatized rocks where the feldspathic component of peg- 
matite is not plentiful, monazite occurs but sparingly. On the 
other hand, monazite is found more abundantly in pegmatized 
rock formations in which feldspar plays a prominent part. The 
common proximity of this form of pegmatization to granite 
masses, or its gradation into pegmatite bodies, gives evidence of 
its formation through magmatic agencies. 
The monazite of rock formations has, then, probably been 
derived from aqueo-igneous solutions such as give rise to certain 
forms of pegmatite and have in these cases affected large masses of 
rock. 
PLACERS 
The commercial deposits of monazite occur in the gravel beds of 
creeks and streams and in the bottom lands adjacent to them. 
The thickness of the gravels ranges from a foot or two, including 
over-burden, to 6 or 8 feet. The distribution of the monazite in 
them is, as with all heavy minerals, richer near the bed rock and 
poorer above, grading into the over-burden. In some deposits the 
whole thickness of the gravel, with the finer alluvium at the sur- 
face, is rich enough to be washed directly or sluiced down and 
washed. The extent and value of these deposits vary with the topog- 
raphy of the country and the nature of the gravels. In some places 
the bottom land, containing rich monazite-bearing gravels, are over 
100 yards wide and extend a half a mile or more along the streams. 
In other places the bottom lands are small and there is but little 
more than the stream gravels present. The best deposits are more 
commonly associated with light colored gravels and sands, con- 
