Notes on mineralogy. No. II. On the chemical composition of the granites of the south-east of Ireland / by Samuel Haughton.

  • Haughton, Samuel.
Date:
[1855]
Catalogue details

Licence: Public Domain Mark

Credit: Notes on mineralogy. No. II. On the chemical composition of the granites of the south-east of Ireland / by Samuel Haughton. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    Table IV.— Isolated Granites. Localities. 1 Silica. Alumina. Peroxide of iron. Lime. Magnesia. Potash. Soda. Loss by ignition. Totals. 70-32 11-24 4-SO 3-01 073 2-27 ;:;-39 1-62 97-38 2. Croghan Kiushela.. 80-24 13 24 0-72 0-89 trace 0-40 5-58 101-07 3. Ballvmotv 66 60 13-26 7-32 336 1-22 2-31 3-60 2-34 100-01 4. Ballynaiuudilagh... 68-56 14-44 5-04 385 0-43 2-78 3-36 1-00 99-46 No. 1. Cushbawn.— Specific gravity, 2*671. A fine-grained granite, contaiiung hornblende in addition to mica. Besides the constituents given in the table, the specimen examined by me contained r34- per cent, of carbonate of lime. No. 2. Croghan Kiushela.— Specific gravity, 2-629. This granite is composed of quartz, felspar and chlorite; the specimen examined appeared to be composed exclusively of quartz and felspar. From the great quantity of soda, I infer that the felspar of Croghan Kinshela is probably albite. On the northern slope of this mountain are situ- ated the old gold streams of Wicklow. No. 3. Ballymoty.—Specific gravity, 2-659. A very fine- grained granite, but containing distinctly felspar, quartz and black mica. No. 4. Bani/namuddaf/h.— ^])ecii\c gravity, 2*670. A coarse- grained granite, with large plates of black mica. Applying to the preceding granites the method of calculation already employed, we find, excluding the granite from Croghan Kinshela, which contains chlorite in place of mica,— Table \\—Atoms of Granitic jMinerals. Atoms of silex = 11. .^toms of peroxide = fK .\tonis of protoxide Atoms of (juartz. Atoms of f<l:;par. Atoms of Uiica. Ciislibawii Ballymoty Ballynaniuddagh... 1-529 1-448 1-490 0-278 0-349 0-344 03U0 0-346 0-325 0067 0-209 0 343 . 0-306 0003 0-019 From the foregoing Table, it appears that the granite of Cush- bawn cannot be considered as a ternary compound of quartz felspar and margarodite, and in fact it contains a sensible nuan-