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On a new mode of occurrence of Ruby in North Carolina

Published online by Cambridge University Press:  14 March 2018

Extract

Parts of the State of North Carolina, with adjoining areas in South Carolina and Georgia, have long been known to mineralogists and geologists as among the most interesting of corundum localities; and the researches of the late Dr. Genth, Col. Joseph Willcox, Mr. J. Volney Lewis and many other authors have done much to make clear the mode of occurrence and associations of corundum in this area and in the great eorundiferous belt stretching along the line of the Appalachian crystalline area from Alabama in the south to Maine in the north.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1899

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References

Amer, Journ. Sci. 4th Ser. Vol. VI. 1898, p. 49.

page 140 note 1 15th Annual Report, 1893-94, U.S. Geol. Survey, Volume on Mineral Resources of the United States (Washington, 1894), p. 693.

Ibid. 16th Annual Report, Part IV. p. 509.

Ibid. 17th Annual Report, Part III. p. 905.

page 141 note 1 The corundum in these gneissose rocks usually occurs in long hexagonal prisms with bassi planes, but no other forms, and the mineral nearly always exhibits purplish tints,

page 144 note 1 Amer. Journ. Sci. 4th Ser. Vol. IV. (1897), pp. 424--428.

page 144 note 2 Neues Jahrb. für Min. &c. 1896, Bd. II. pp. 197-238.

page 145 note 1 The rhodolite of the Cowec-Creck and Mason'e Branch district has been recently earsfully studied by Dr. Pratt in conjunction with one of us.

This analysis corresponds, almost exactly, to a combination of two molecules of the magnesium-aluminium garnet(pyrope) with one molecule of a ferrous ironaluminium garnet (almandine). There is considerable variation in the tint of shodolite, the approach being sometimes towards the pyrope eolours, at others towards the almandine. Probably the proportion of the two molecules is by no means constant. In spite of the preponderance of the pyrope molecule, as shown by analysis, an examination of the absorption bands of rhodolite, which was kindly made for us by Professor Church, F.R.S., shows that it gives the same characteristic spectrum as is found in ahnandine.

page 147 note 1 For fuller details concerning these accompanying minerals with analyses consult a paper "On the Associated Minerals of Rhodolite," by W. E. Hidden and J. H. Pratt. Amer. Journ. Sci 4th Ser. Vol, YI. (1898), pp. 463-468.

page 147 note 2 Zeits. Kryst. Vol. XXIV. (1895), p. 281, and Tgdwrm. Min. und Petrog. Mitt. (Neue Folgt), Vol. XVIII. (1898), pp. 1-90, 105--240.

page 148 note 1 Zeits. Kryst. Vol. XXIV. (1895), p. 285.

page 148 note 2 " Corundum-bearing Book from Yogo Gulch, Montana," by L. V. Pirsson. Amer. Journ. Sci 4th Ser. Vol. IV. (1897), p. 421. " Crystallography of the Montana Sapphires," by J. H. Pratt. Ibid. p. 424.

page 148 note 3 Neues Jahrb. Min. &o., 1896, Bd. IL Tat, VII.

page 149 note 1 Phil. Trans. Vol 187A (1896), pp. 151-228.