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South African occurrences of willemite. Fluorescence of willemite and some other zinc minerals in ultra-violet rays

Published online by Cambridge University Press:  14 March 2018

L. J. Spencer*
Affiliation:
British Museum (Natural History)

Extract

Willemite is a mineral of comparatively rare occurrence, but it has long been mined in New Jersey as an important, ore of zinc (Zn2Sio4, containing Zn 58.6 %), and it would seem also to be abundant in Rhodesia. In the standard mineralogies of Dana (1892) and Hintze (1889) it is mentioned from only four districts. As there is some confusion in the statement of these few localities, and further as several others have been discovered during recent years, a complete list of localities for this mineral has been compiled from the literature; and some others represented by specimens in the British Museum collection are added, inchding the African occurrences now to be described.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1927

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References

page 389 note 1 So named from the iron furnace where cannon were cast during the American war of independence (1775-1781). It is also known as Franklin, both names being in common use. At the time of my visit in 1924, the railway station was labelled ‘Franklin Furnace’ and the post office ‘Franklin’. The name Franklin Furnace is here adopted, since Franklin is a very common placename in the United States, there being, for instance, at least six other such places in New Jersey alone.

page 389 note 2 Also spelt Sterling Hill, but evidently named after William Alexander (1726-1783), titular Earl of Stirling, a former owner of the land. He sent several tons of ‘red ore’ from there to England for the manufacture of brass about 1774; i. e. long before zincite was recognized as a mineral-species. ‘Sparta', the name of the township, is sometimes quoted as the locality for willemite.

page 389 note 3 Given in some of the old books as ‘Old Mountain in Limburg’.

page 390 note 1 H. Buttgenbach. La calamine des ossements fossiles de Broken-Hill (Rhodésie). Ann. Soc. Géol. Belgique, 1919, vol. 42, Congo annexe, pp. c5–c14 (Min. Abstr., vol. 1, p. 69). Microscopical crystals of willemite and some other zinc minerals were recognized by their optical characters in the central cavity of limb bones. Appended is the following note (p. c 14):

‘Enfin, je signale de jolis cristaux légèrement brunâtres, de willénite [sic] accompagnant de lu descloizite : ees erietaux ont la forme habituelle du prisme hexagonal surmonté d'un rhomboère très obtus. La willémite n'a pas encore été signalée à Broken-Hill.’

page 391 note 1 Spencer, L. J., On hopeite and other zinc phosphates and associated minerals from the Broken Hill mines, North-Western Rhodesia. Min. Mag., 1908, vol. 15, pp. 138 Google Scholar.

page 391 note 2 Speak, S. J., An occurrence of zinc silicate ore of supposed primary origin. Bull. Inst. Mining Metall. London, February 1926, no. 257, 5 Google Scholar pp., 2 pls. ; Transactions, 1926, vol. 35 (for 1925-6), pp. 226-247, 2 pls.

page 393 note 1 Similar to the crystals from Broken Hill, Rhodesia, on whieh E. D. Mountain has recently given accurately determined constants for smithsonite (Min. Mag., 1926, vol. 21, p. 51).

page 394 note 1 A similar occurrence of native silver with dioptase (and willemite) in limestone is known from Mindouli, French Congo ( Lacroix, A., Min. de France, 1910, vol. 4, p. 841 Google Scholar).

page 396 note 1 Kunz, Gr. P. and Baskerville, C., The action of radium, Roentgen rays and ultra-violet light on minerals and gems. Science, New York, 1903, n. ser., vol. 18, pp. 769783 Google Scholar. (Willemite on p. 774.)

page 396 note 2 Ernst Engelhardt, Lumineszenzerscheinungen der Mineralien im ultravioletten Licht. Inaugural-Dissertation, Univ. Jena, 1912, 42 pp.; Abstract in Neues Jahrb. Min., 1913, vol. ii, p. 358.

page 396 note 3 Liebisch, T., Über die Fluoreszenz der Sodalith- and Willemitgruppe im ultravioletten Licht. Sitzungsber. Preuss. Akad. Wiss. Berlin, 1912, pp. 229240 Google Scholar.

page 396 note 4 Andrews, W. S., Notes on the preparation of some fluorescent and phosphorescent compounds. Amer. Min., 1922, vol. 7, pp. 1923 Google Scholar. [Min. Abstr., vol. 2, p. 22.]