单词 | pegmatite |
释义 | pegmatiten. Geology. A coarsely crystallized rock commonly occurring in igneous intrusions, esp. dykes, and consisting mainly of feldspar and quartz, with the crystals often forming a graphic surface pattern. ΘΚΠ the world > the earth > structure of the earth > constituent materials > rock > igneous rock > [noun] > plutonic rocks > granite > varieties of moorstone1461 silver stone1758 granitell1794 granitoid1794 rapakivi1794 ophthalmite1811 protogine1823 pegmatite1824 potash-granite1845 beresite1849 granitite1875 greisen1878 trowlesworthite1884 microgranite1888 charnockite1893 alaskite1900 Dartmoor granite1904 plagiogranite1959 1824 T. Say in W. H. Keating Narr. Exped. St. Peter's River II. App. i. §1. 365 The only rock composed by the union of these two principles which we did not observe..is the graphic granite (Pegmatite, Haüy). 1832 C. Darwin in Life & Lett. (1887) I. 238 At Bahia the pegmatite and gneiss in beds had the same direction. 1871 Amer. Naturalist 5 461 The great gneissic area..is cut by numerous veins of pegmatite, holding garnet, tourmaline and beryl. 1957 H. S. Zim & P. R. Shaffer Rocks & Minerals 56 Olframite..is a mineral of quartz veins and pegmatites. 1993 Jrnl. Petrol. 34 840 Mafic enclaves are observed at some localities, and aplite/pegmatite veins cut across some outcrops. This entry has been updated (OED Third Edition, September 2005; most recently modified version published online March 2022). < n.1824 |
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