Англо-русский научно-технический словарь:
perlite
=
pearlite
Англо-русский политехнический словарь:
perlite
перлит
Merriam-Webster's Collegiate Dictionary:
perlite
noun
Etymology: French, from
perle pearl
Date: 1833
volcanic glass that has a concentric shelly structure, appears as if composed of concretions, is usually grayish and sometimes spherulitic, and when expanded by heat forms a lightweight aggregate used especially in concrete and plaster and as a medium for potting plants
•
perlitic adjective 
