Perlite

= pearlite

Англо-русский научно-технический словарь

Perlite

перлит

Англо-русский политехнический словарь

Perlite

noun Etymology: French, from perle pearl 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

Merriam-Webster's Collegiate Dictionary