出典:Wiktionary
出典:『Wiktionary』 (2026/04/20 17:08 UTC 版)
From Anglo-Norman and Old French pomis (“pumice stone”), from Latin pūmex (“pumice stone”). Doublet of pounce.
pumice (countable and uncountable, plural pumices)
pumice (third-person singular simple present pumices, present participle pumicing, simple past and past participle pumiced)
出典:Wikipedia
出典:『Wikipedia』 (2011/06/28 22:34 UTC 版)
Pumice (
/ˈpə.məs/) is a textural term for a volcanic rock that is a solidified frothy lava typically created when super-heated, highly pressurized rock is violently ejected from a volcano. It can be formed when lava and water are mixed. This unusual formation is due to the simultaneous actions of rapid cooling and rapid depressurization. The depressurization creates bubbles by lowering the solubility of gases (including water and CO2) dissolved in the lava, causing the gases to rapidly exsolve (like the bubbles of CO2 that appear when a carbonated drink is opened). The simultaneous cooling and depressurization freezes the bubbles in the matrix.
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