Monazite and Monazite Mining 
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150 miles long. This belt lies wholly within the Piedmont Pla- 
teau and borders closely on the Blue Ridge, to whose general 
course it is roughly parallel. 
Geology 
Formations 
The rocks of the Carolinas monazite region are principally 
gneisses and schists. These include the Carolina and Roan 
gneisses; granite gneiss and porphyritic granite gneiss. Among 
other rocks are massive granite, pegmatite, peridotite and allied 
rocks, quartz diorite, and diabase. 
The Carolina gneiss is of Archaean age and is the oldest and 
most important rock of the region. It is composed of several 
types of gneisses and schists which exhibit various degrees of 
metamorphism. The most common types are mica, garnet, 
cyanite, and graphite gneisses and schists or combinations of two 
or more of these types. The mica of the micaceous types may be 
either biotite or muscovite or both. More or less mica is generally 
present in all of the types of the Carolina gneiss, while the garnet 
and cyanite types with or without the graphite type also occur 
together. The different types of the Carolina gneiss vary in color 
from light gray to dark gray and are sometimes bluish gray or 
bluish black where graphite is abundant in them. Some types of 
the Carolina gneiss are fine grained so that the component miner- 
als are distinguished with difficulty, while others are more coarsely 
crystallized. Some of the common constituent minerals of the 
Carolina gneiss are biotite, muscovite, quartz, garnet, cyanite, 
feldspar, and graphite. The presence of much pegmatitic 
material is a characteristic feature of much of the Carolina gneiss. 
The Roan gneiss is the next oldest formation of the monazite 
region and is also of Archaean age. It consists of hornblende 
gneiss and schist, with occasionally the less metamorphosed phase 
diorite. The hornblende gneisses and schists are composed chiefly 
of small interwoven and matted hornblende crystals and grade 
into diorite which contains a noticeable amount of feldspar and 
has a granitoid texture. The hornblende rocks vary from black 
to dark green in color. Bands of mica gneiss and schist, possibly 
of the Carolina gneiss, are included in both large and small 
masses of the Roan gneiss. 
