Perlite

Perlite softens when it reaches temperatures of 850–900 °C (1,560–1,650 °F). Water trapped in the structure of the material vaporises and escapes, and this causes the expansion of the material to 7–16 times its original volume. The expanded material is a brilliant white, due to the reflectivity of the trapped bubbles. Unexpanded ("raw") perlite has a bulk density around 1100 kg/m (1.1 g/cm), while typical expanded perlite has a bulk density of about 30–150 kg/m (0.03–0.150 g/cm).

70–75% silicon dioxide: SiO2

12–15% aluminium oxide: Al2O3

3–4% sodium oxide: Na2O

3–5% potassium oxide: K2O

0.5-2% iron oxide: Fe2O3

0.2–0.7% magnesium oxide: MgO

0.5–1.5% calcium oxide: CaO

3–5% loss on ignition (chemical / combined water)

Perlite has many uses in construction, including as a main ingredient in plaster and mortar, as well as in veneers for ceramic tiles and stucco. It is commonly used in insulation as a fireproofing agent. Perlite also has horticultural uses, commonly added to soil in houseplant pots to provide greater aeration without adding much weight.

Perlite is a non-renewable resource. The world reserves of perlite are estimated at 700 million tonnes. The confirmed resources of perlite existing in Armenia amount to 150 million m, whereas the total amount of projected resources reaches up to 3 billion m. Considering specific density of 1.1 ton/m confirmed reserves in Armenia amount to 136 mln. tons. Other reported reserves are: Greece - 120 mln. tons, Turkey, USA and Hungary - about 49-57 mln. tons. Perlite world production led by China, Turkey, Greece, USA, Armenia and Hungary summed up to 4.6 mln. tons in 2018.

70–75% silicon dioxide: SiO2 12–15% aluminium oxide: Al2O3 3–4% sodium oxide: Na2O 3–5% potassium oxide: K2O 0.5-2% iron oxide: Fe2O3 0.2–0.7% magnesium oxide: MgO 0.5–1.5% calcium oxide: CaO 3–5% loss on ignition (chemical / combined water)