perlite
noun
- Geol. a greenish volcanic glass, similar to obsidian, with a pearly luster and multiple, minute concentric cracks, used as insulation and in making concrete, plaster, etc.
- pearlite
See perlite in American Heritage Dictionary 4
also pearl·ite (pûrˈlītˌ)
noun A natural volcanic glass similar to obsidian but having distinctive concentric cracks and a relatively high water content. In a fluffy heat-expanded form perlite is used as a lightweight aggregate, in fire-resistant insulation, and in soil for potted plants.
Related Forms:
- per·litˈic (pər-lĭtˈĭk) adjective
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