lapilli

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lapilli Pyroclastic fragments or tephra ranging in size from 2 to 64 mm. Lapilli may be composed of primary magmatic material (e.g. pumice), accessory lithic material, accidental lithic material, or accretions of wet ash-size material (accretionary lapilli). The size-term ‘lapilli’ is usually applied to the lithological clast type to give descriptive terms, e.g. ‘pumice lapilli’ or ‘accessory lithic lapilli’.

lapilli

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lapilli fragments of stone from a volcano. XVIII. —pl. of It. lapillo— L. lapillus, dim. of lapis stone.