The vermiculite is a kind of silicate mineral that can be extracted from the rocks. Many of them are treated with heat and high pressure so that in this way it can expand and later be used in different industrial materials . Its expansion process causes a very porous surface to form and this gives it the great ability to retain moisture and different nutrients , especially when used in the field of agriculture or plantations. Thanks to it, soils must be watered less frequently as it is capable of holding moisture for a long time.



  • Crystal system: Monoclinic
  • Hardness: 2 – 3
  • Specific gravity: 2.4 – 2.7

What is vermiculite?

Vermiculite is a mineral that belongs to the Micas family and is composed of iron and magnesium silicates , which when mixed with other ingredients increases their water retention properties in plants.

  • Vermiculite characteristics
  • Properties
  • What is it for
  • Toxicity
  • Types of vermiculite
  • Where you can buy
  • Importance

Vermiculite characteristics

Vermiculite is a mineral that is characterized by being composed of iron , aluminum and magnesium among other minerals. It has a laminar structure that allows it to store large amounts of water inside. When faced with high temperatures, it tends to suffer from an extension which it does at the same time that it produces a series of metallic reflections . Their porosity is quite high and they generally have a brown color which can vary depending on the proportion in which the elements that compose it are present.

Its pH is neutral , its weight is light and an important characteristic is that it has the ability to stay free of diseases , weeds and insect pests . It has light reflection and is bright. It is a material that is widely used in the field of planting and agriculture . It is also visually attractive and that is why it is used in home pots.


Among the main properties that can be found in vermiculite, the following are mentioned:

  • It has a hardness of 2.
  • Its chemical formula is Mg 0.7 (Mg, Fe, Al) 6 (Si, Al) 8020 (4.8H2O).
  • It belongs to the group of minerals known as phyllosilicates .
  • It has a yellowish color that can vary.
  • It can be mixed with other ingredients.
  • It has a very good insulation capacity so it can withstand temperatures between 200 ° and 1200 ° Celsius.
  • It is fire resistant and its weight is light.
  • Its density is around 60 and 140 KG / m3.
  • It also has acoustic insulation against sound waves and different frequencies.
  • It has a thermal conductivity of approximately 0.053 kcal / hm when it is at a temperature of 20 ° C.
  • Its melting point is 1370 ° C.
  • It is also resistant to different atmospheric changes , which makes it insensitive to changes in the environment in which it is found.

What is it for

Vermiculite is a mineral widely used mainly in agricultural work thanks to its great moisture retention capacity , which at the same time generates a greater amount of nutrients for plants. It also works as a type of fertilizer because it has important minerals in its constitution such as calcium, potassium and magnesium, all of them key in the proper and effective cultivation of plants.

It can also be used as a mixture with other minerals and elements such as coconut fiber and perlite, to later be used in seedbeds and potted crops . It is used, thanks to its insulating capacity in the combustion chambers that are placed in the milk stoves, as they considerably increase the performance of the appliance, modernize its design and reduce manufacturing and maintenance costs.

In some cases, vermiculite is used in the construction field because it has quite important insulating properties, whether it is used to isolate sound or fire . Studies and experiments have been done indicating that it can also be used in the manufacture of some drugs and works as a means of retaining moisture in the construction of places that are usually affected by floods.


A number of studies have been conducted looking for the toxicity of vermiculite. Many scientists claim that it contains asbestos , a carcinogen that poses great health risks as well as other materials that can be toxic, however its toxicity is still under study. For a time it was associated with the presence of asbestos , however, this was eradicated as it actually only occurred in a mine in Montana , which was closed .

Types of vermiculite

There are two different types of vermiculite, both of which are listed below.

  • Raw vermiculite: this is the type of vermiculite in its natural state , in other words, when it has not been subjected to any type of procedure and has not been exposed to high temperatures. When raw, it can be divided into five primary grades depending on the size of its particles, in such a way that they can be large, medium, fine, super fine and micron.
  • Exfoliated vermiculite : this is the type of vermiculite that can already be purchased in the market , it can also be found in five different grades but in this case, the classification will be made depending on the weight of the particles and not on the size. It can then be found as micron, super fine, fine, medium and large degrees. These types of vermiculites will be used depending on the needs of the soil and the results that are being sought.

Where you can buy

Vermiculite is a product that can be purchased from virtually any garden or farm supply store . Many times it can be purchased directly from veterinarians, large supermarkets, and even online.


Its main importance is in the field of agriculture and gardening because thanks to its properties and the minerals that make it up, when combined with compost or soil, it has the great capacity to promote a better and faster growth of the roots of the plants. Thanks to it, plants can better retain air, food and moisture, allowing them to take it when necessary.

It is also very important in the field of transporting some types of materials as it is used to transport dangerous liquids with greater safety, thanks to its absorbent properties that can stop any type of leak that may occur. It is a powerful protector against fire because it is also nonflammable what makes it the ideal material for various pack types of batteries, to name a few example. Finally, it is one of the favorite materials to be able to isolate places from high volumes of sounds .

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