Mineral Resources Potential - Geothermal Resources

144 Mineral Resources Potential of Ethionia
4.12 Quartz
Occurrence
Quartz occurs in hydrothermal veins and pegrnatites. Well-formed
crystals may reach several metres in length and width hundreds of
kilometers. These veins may bear precious metals such as gold or
silver, and form the quartz ores sought in mining. Erosion of
pegrnatites may reveal expansive pockets of crystals, known as
"Cathedrals." Quartz is a cpnmon constituent of granite,
sandstone, limestone, and many other igneous, sedimentary, and
metamorphic rocks. Trid y mite and cristobalite are high
temperature polymorphs of SiOz which occur in high silica
volcanic rocks. Lechaklierite is an amorphous silica glass SiOz
which is formed by lightning strikes in quartz sand,
Applications
Many varieties of quartz are used in jewelry and for ornamental
purposes. Agate and chalcedony are used in scientific instruments,
chemical and radio apparatus. Ground and crushed quartz are used
in wood filler, ceramics, glass, polishing soap and as an abrasive. It
is also used as a flux in metallurgical work and in making
refractory bricks.
Quartz deposits in Ethiopia
Quartz occurs widely in the basement rocks, in the form of veins
and as a component of pegmatites. Several quartz vein and quartz-
bearing pegmatites occur in the Kenticha area, with estimated
resource of 0.26 Mt (Ethiopian.'Mineral Development Sh. Co) of
good quality that can be used for glass and ceramics factories.