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Bafalt. 233 moved the magnetic needle. 1 Chy. Än. 1788, 412. Frequently fonorous when ftruck. Gives a grey ftreak. When heated reddens. I melted that of Saxony into a black glafs at ioo°, fo compact that its fp. gr. was Hill 2,8591 at 130° its glafs is ftill more coinpadt, According to Mr. Bergman, it confifts of the fame principlcs as trap, and in the fame propor- tion. It almoft al ways contains particles of balal- tine, fometimes alfo hornblende, the German bafalts contain alfo olivins; but thefe laft are not found in the Irifli; alfo, though more rarely, felfpar, quartz, zeolytes, Ihorl, and fpar, Micas are fcarce ever found in it, though fometimes upon it. Wacken, on the contrary, never exhi- bits olivins. ijjth Species. Calp, or black quarry ftone of Dublin, Colour, bluifh black, or dark greyifh blue, variouüy interfeäed with veins of white calcareous fpar, and often invefted with the fame. Found in large mafles. Luftre, o,* except a few fhining particles of fpar. Tranfparency, o. Fradture, exceeding fine fplintery, paffing into theeven, and fometimes into the imperfeö, con- choidal. Fragments, 2. In the diredtion of its ft rata it eafily fplits into large flaggs, Hardnefs,