MAJOR RAW MATERIAL Perlite is not a trade name but a generic term for naturally occurring silicous rock. The distinguishing feature which sets perlite apart from other volcanic glasses is that when heated to a suitable point in its softening range, it expands from four to twenty times its original volume. METHOD OF APPLICATION ABTEC Perlite is mainly used for making soil - less hydroponic medium for plant growth. For this take 1 part ABTEC Perlite, 1 part Exfoliated Vermiculite and 3 parts Coirpith compost and mix together. ABTEC Perlite can also be added to soil to increase the aeration and water holding capacity of soil.