Shirasu is a natural inorganic ceramic material created by magma, which we refer to as “magma ceramic”. Shirasu is also known as “amorphous volcanic glass”, and possesses an amorphous portion ranging from 60% to 80%, giving it unique properties which distinguish it from other volcanic products.

Being highly amorphous, its molecular composition is unstable and activated, and according to the environment, it easily causes a catalytic reaction.. Therefore, it inherently exhibits functions such as deodorization, decomposition, sterilization, and ionization.

Shirasu has a porous structure featuring numerous holes in extremely fine particles.
Silicate, which is a major constituent of shirasu, is a major source material used in the manufacturing of dehumidifying agents, and is the source of the superior humidity control function of Shirasu-kabe.
Also, the alumina contained in shirasu has a naturally strong gas absorption function which causes odors and chemical molecules to be absorbed into the cavities of the shirasu particles.
A unique feature of shirasu is its extremely complex structure and composition, which cannot be created artificially. This feature differentiates shirasu from the volcanic products of other regions.

Conposition of shirasu

Soil is rock that has been weathered into powder. It develops over a long period of time, affected by various environmental factors such as biological and meteorological influences. Soil supplies nutrients and water to plants and is an essential provider for the foundations of all organic life, starting with us – humans.

Shirasu, in turn, is the result of a pyroclastic flow of magma which instantaneously cooled as it erupted, and has the same physical characteristics as finely ground inorganic rock. It therefore can be considered a primitive soil that is untouched by the actions of plants or microorganisms.

Magma erupting into ancient oceans was slowly cooled into minerals that gradually dissolved and released various elements and compounds. The oceans became a ‘magma soup’ of complex molecules that eventually formed into proteins. Over millions of years of evolution, these proteins gave rise to all life as we know it today, including even ourselves.

Since shirasu is a special soil that is born from magma, it can be said that magma itself is a distant ancestor of shirasu, and therefore also of humans, who share a deep, longstanding, living bond with the soil.