Perlite is a naturally occurring volcanic glass that expands when heated. It is a type of amorphous volcanic glass, but it differs from typical glasses in that it contains a significant amount of water. When heated, the water trapped in the perlite vaporizes, causing the material to expand and become a lightweight, white, granular substance.

Here are some key points about perlite:

1. Formation: Perlite is formed when obsidian, a type of volcanic glass, comes into contact with water. Over time, the glass traps water in its structure, and when it is mined and heated, the water turns into steam, causing the material to expand.
2. Lightweight and Insulating: One of the primary characteristics of perlite is its lightweight nature. The expansion process that occurs when it is heated results in a material with a low density. This makes perlite useful in horticulture, construction, and other applications where a lightweight and insulating material is desirable.
3. Horticultural Uses: In gardening and horticulture, perlite is often used as a component of soil mixes. Its lightweight and porous nature help improve aeration and drainage in soil, preventing it from becoming compacted. This makes it an excellent addition to potting mixes for various plants.
4. Construction Applications: perlite is used in the construction industry as an aggregate in lightweight concrete and plaster. The lightweight properties of perlite concrete make it advantageous in applications where reduced structural load is important, such as in the construction of walls, roofs, and floor fills.
5. Fireproofing: Due to its insulating properties, perlite is also used in fireproofing applications. When mixed with other materials, it can provide fire resistance in construction.
6. Industrial Filtration: Perlite’s porous structure makes it suitable for use in filtration applications. It is commonly used as a filter aid in various industries, including food and beverage processing.
7. Expanded Perlite vs. Crushed Perlite: Perlite can be found in two main forms—expanded and crushed. Expanded perlite is the lightweight, porous material produced by heating raw perlite. Crushed perlite, on the other hand, is the raw material before it undergoes the expansion process. The choice between the two depends on the specific application requirements.

In summary, perlite is a versatile material with uses ranging from horticulture to construction. Its lightweight and insulating properties make it valuable in various industries, contributing to its widespread application in different fields.