WHAT IS PUMICE?
The leightest rock that can even float on the water and
the softest natural abrasive media.
Pumice is a type of extrusive volcanic rock, produced
when lava with a very high content of water and gases (together
these are called volatiles) is extruded (or thrown out
of) a volcano. As the gas bubbles escape from the lava,
it becomes frothy. When this lava cools and hardens, the
result is a very light rock material filled with tiny
bubbles of gas. Pumice is the only rock that floats on
water, although it will eventually become waterlogged
and sink. It is usually light-colored, indicating that
it is a volcanic rock high in silica content and low in
iron and magnesium, a type usually classed as rhyolite.
In commerce, pumice is the term applied to larger pumice
stones, while pumicite consists of fine grains or ash.
Pozzolan is a fine-grained pumicious material (both
natural and man-made), which combines with lime to make
a smooth, plaster-like cement. These three similar
materials may be found and mined together, but they have
different characteristics and different uses
Pumice is seperated from the similiar glassy volcanic
rocks ( such as perlite, obsidian, pumice pearlitic) by
some distinctive pores. Practically, seperated from
these by colour, porosity and lack of crystal water. It
is most widely-confused with perlite by colour
similarity/proximity and chemical composition, in some
cases it could be harder to differentiate from perlite.
It can be distinguished from the transitive rocks which
could be called as Perlit with Pumic/ Pumtic Perlit or
Pearlitic Pumic by petrographic analysis, and pore
The unique properties of pumice are the result of its
origin as volcanic lava that underwent the simultaneous
actions of rapid cooling and rapid depressurization. The
rapid cooling and depressurization that pumice underwent
resulted in a network of porous voids within the glass
structure, similar to a sponge. This is the reason for
the light weight and mildly abrasive nature of pumice
that accounts for many of its industrial applications.
While pumice is an igneous rock, it is actually a kind
of non-crystalline glass and not a mixture of minerals.
The physical properties of pumice are governed by the
extremely cellular structure of the matrix. These cells
are independent of each other, which means that the
level of sound and heat conductivity are both extremely
low. The hardness of pumice is approximately 5.5-6 on
the mohs scale. It does not contain crystalised water in
it's structure. It is chemically inert and possesses
about 75% silisium oxide. Due to the microscopic size of
the pores, which make up about 85% of the pumice grain
volume, pumice is an extremely light rock which is able
to float on the surface of water for a long time.
General Chemical Composition of Pumice
trace amounts of TiO2 and SO3
SiO2 ratio that the rock contains in gives abrasive
property to rocks. So it is a chemical structure that
abrasives steel easily. Al2O3 composition gives high
strength to heat and fire. Na2O and K2O are known as the
minerals that shows reaction properties in the textile
Turkiye has an important potential in terms of many
industrial raw materials and underground sources. At the
same time, pumice has a very important place among the
mineral resources for Turkiye which has 40% (more
than7,2 billion m³) of world reserves that is around 18