European Journal of Scientific Research (ISSN: 1450 ... - EuroJournals

© European Journal of Scientific Research, Vol 7, No 5, 2005
mica, however, the United States leads the world in the production of scrap mica. High quality
muscovite is characteristic of granite and granite pegmatites, associated with quartz and
feldspars. The micas are often found in large crystal aggregates called books, which can be
many feet in length. The low yield product that is in major production in the United States is
used extensively in heat and electrical insulators.
In recent times in Nigeria, there has been increasing exploration and exploitation of local raw
material for industries in order to save foreign exchange and to ensure rapid industrialization.
High quality muscovites occur in the granite pegmatite complex of Nigeria which occurs as a belt
that extends from southwestern Nigeria to central Nigeria and covers a distance of over
250kilometers. The pegmatites form isolated outcrops in the generally resistant granite gneiss
complex that form the country rocks. The hosting pegmatites may be tabular, lensoidal or
irregularly shaped generally trending N-S of the enclosing granitic country rocks. Both
pegmatites and host granites are mineralogically similar. The muscovite deposits occur as pockets
discontinuously along this belt. In some places however extensive and minable deposits are
found.
The samples which are the subject of this study were taken from deposits in Ijero-Ekiti and Ile-Ife
southwestern Nigeria. The muscovites usually occur as sheets in the core and intermediate zones
of the pegmatites and are oriented roughly perpendicularly to the borders, suggesting growth into
the open space.
Samples Ije – mc 1-2 series from Ijero are grayish, almost white muscovites associated with a
quartz tourmaline pegmatite in Ijero. The Ijero pegmatite is a quartz-alkali feldspars-muscovite
body with primary cassiterite, beryl and tourmaline in subordinate proportions. It is located in an
extensively pegmatized belt in the migmatiitic gneisses of the basement complex outcropping
about 2 kilometres northwest of Ijero, southwestern Nigeria on longitude 50 5’E and latitude 7 0
50’N. Almandite is well developed in both the pegmatized belt and the surrounding gneisses.
Economically, the pegmatite has yielded moderate amount of tin.
Samples Ife - mc 3-5 series are whitish to brownish muscovites from a quarry along Ife-Ondo
road. The host rock is a quartz potassium and biotite bearing granite pegmatite with subordinate
tourmaline crystals. The pegmatite body occupies the middle portion of a 10 meter vertical face
in the quarry and trends approximately in a north-south direction. It has an average width of