The name of zeolite comes from a Greek word that means "a stone that is boiling." So, the ore is also called "boiling stone." Zeolite includes water molecules (H₂O) in the form of crystallization water as a major element in the structure; that is, zeolite is the hydrous silicate ore with aluminum. If heated extremely, zeolite melts with bubbling moisture, which looks like a stone boiling. Thus, the name is so given.

The crystallization water of zeolite is in the form of water molecules existing in the framework structure of zeolite. So, this is particularly called "zeolitic water." Even when dehydrated by heating or the like, the structure of zeolite is not destroyed. The space areas, where crystallization water used to be, remain as they are in the form of a cavity. This looks like the structure of a piece of sponge. Zeolite, according to its characteristics, strongly absorbs gas and moisture into those cavities.

Another one of the conspicuous characteristics of zeolite is its base exchange capacity. This is also called positive ion exchange capacity (cation exchange capacity: C.E.C.), which means the force that holds or releases positive ions (, potassium, sodium, calcium, etc.) as if a magnet is working. In particular, the base exchange capacity of zeolite is called permanent charge. This is not under the influence of the environment (PH or the like) in the vicinity. The force is maintained for a long period according to the characteristics.

Zeolite is classified into many types depending its structure. When it comes to natural zeolite materials, they can be classified into two major types: mordenite zeolite and clinoptilolite zeolite. These two scarcely exist alone. They usually exist with other ores. When you find something called zeolite on market, you should be careful because its purity may be often low.

In recent years, the global environmental pollution is of our great concern. Zeolite is particularly attracting our attention because of its purification capability. One of the representative examples was the "Soil Fertility Enhancement Act," which was enforced in 1984. This law was formulated from scratch at that time in order to revive the soil that was cold and devastated by chemical fertilizers into the soil that was as rich and bountiful as it used to be. According to the law, zeolite was designated as a material for the improvement of the soil. In addition to this, zeolite is a material that is effective and efficient as a type of ore for the purification of the soil, water, and air in the 21st century. This ore will be attracting more attention in the coming days.

Photos of natural zeolite with a scanning electron microscope（×5000）

Note;
The theoretical value of the base exchange capacity is 223meq with mordenite of 100% purity. When the measurement of Nitto zeolite is converted accordingly, the purity is as high as 71% to 85%.