| 释义 |
pitchstone Min.|ˈpɪtʃstəʊn|
[f. pitch n.1 + stone n., tr. Ger. pechstein (Werner 1780).]
a. An old volcanic rock; obsidian or other vitreous rock looking like hardened pitch.
b. = pitch-opal.
1784Kirwan Min. 97 Pitch-stone, lava. 1796― Elem. Min. (ed. 2) I. 292 Pitchstone.. It often much resembles semi opals and jaspers. 1799― Geol. Ess. 180 Huge strata..as they contain abundance of quartz and felspar may be called pitchstone porphyry. 1807J. Headrick Arran 58 On the northern declivity saw many masses of pitchstone. 1836Macgillivray tr. Humboldt's Trav. iii. 51 Lavas with a basis of pitchstone and obsidian. 1894Times 11 Aug. 11/2 Invaded by the pitchstone-lava of the island of Eigg. |