2. CLAY AND ITS
PROPERTIES
Clay is an inherently occurring material
constituted with fined-grained mineral. The
minerals are generally less than 2 microns
and occur to be plastic in water content which
solidify when dried.
The small size of the particles and their unique
crystal structures give clay materials special
properties. These properties include: cation
exchange capabilities, plastic behaviour when
wet, catalytic abilities, swelling behaviour, and
low permeability.
3. FORMATION OF CLAY
Clays and clay minerals occur under a fairly limited range
of geologic conditions. The environments of formation
include soil horizons, continental and marine sediments,
geothermal fields, volcanic deposits, and weathering rock
formations. Most clay minerals form where rocks are in
contact with water, air, or steam. Examples of these
situations include weathering boulders on a hillside,
sediments on sea or lake bottoms, deeply buried sediments
containing pore water, and rocks in contact with water
heated by magma (molten rock). All of these environments
may cause the formation of clay minerals from preexisting
minerals. Extensive alteration of rocks to clay minerals can
produce relatively pure clay deposits that are of economic
interest
4. CLAY VARIETIES
Clay comes in many varieties with different
propertes. Different clays are suitable for
different uses and situations. Some clay is
particularly strong and durable, making it
ideal for large-scale or outdoor use. Other
types are chosen for their colour, texture or
flexibility.
Popular types of clay include earthenware,
stoneware and porcelain
