| 单词 | high-cristobalite |
| 释义 | > as lemmashigh-cristobalite One of the three main forms of silica (the others being quartz and tridymite), formed at high temperatures as high-cristobalite and changing at lower temperatures to a structurally related metastable polymorph, low-cristobalite, which occurs both massive (e.g. in opal) and as small, usually octahedral, crystals. ΘΚΠ the world > the earth > minerals > types of mineral > silicates > tectosilicate > [noun] > quartz > high temperature quartzes tridymite1868 cristobalite1888 1888 Min. Mag. VIII. 36 A New Mineral. Cristobalite... An analysis..gave 91 per cent. of silica and 6 per cent. of oxide of iron and alumina. 1920 Brit. Museum Return 144 Artificial minerals (cristobalite, fayalite, rhodonite, apatite, spinel..) from furnace slags. 1925 J. Joly Surface-Hist. Earth iii. 64 Quartz..undergoes an allotropic modification..at atmospheric pressure. It changes into cristobalite—which is a low-density form of quartz. 1935 Discovery July 206/1 When ware is fired above a certain temperature a very large number of extremely fine crystals of a mineral (crystobalite) are formed. 1959 Chambers's Encycl. IX. 423/1 Both cristobalite (stable 1,470°–1,710° C) and tridymite (stable 870°–1,470° C) are known to occur in certain natural lavas. 1962 C. Frondel Dana's Syst. Mineral. (ed. 7) III. 287 In recent years..study has shown that opal..is a submicrocrystalline aggregate of crystallites of cristobalite. < as lemmas |
| 随便看 |
英语词典包含1132095条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。