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Morphology, twinning, and optical orientation of gismondine

Published online by Cambridge University Press:  05 July 2018

Rab Nawaz*
Affiliation:
Department of Geology, Ulster Museum Belfast BT9 5AB

Summary

Gismondine is a monoclinic mineral but prior to X-ray determination of its unit cell it was variously regarded as orthorhombic, monoclinic, or triclinic on account of its intricate twinning. A study of gismondine crystals from Osa Quarry, near Rome, indicates that the morphologically dominant form is {32} which by twinning about the normal to {100} produces penetration-twinned octahedral crystals united on (100) and (001). Gismondine has poor cleavage on {32} optic plane is (010) and γ:[001] = 42.5° (in obtuse β).

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1980

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References

Dana, (E. S.), 1892. The System of Mineralogy, 6th edn., 586.Google Scholar
Des Cloizeaux, (A.), 1883. Bull. Soc. Mineral. France, 6, 300.Google Scholar
Donnelly, (T. W.), 1967. Am. Mineral. 52, 112.Google Scholar
Fischer, (K.), 1963. Am. Mineral. 48, 664-72.Google Scholar
Fischer, (K.) and Kuzel, (H.), 1958. Naturwiss. 45, 488.CrossRefGoogle Scholar
Gismondi, (C. G.), 1816. [Osserv. Mineral. Roma], transl. K. C. yon Leonhard, Tasch. Mineral. 11, 164 (1817).Google Scholar
Kalb, (G.), 1932. Z. Kristallogr. 81, 248-52 [M.A. 5-163]Google Scholar
Kraus, (O.), 1939. ZentralbL Mineral., Abt. A, 105-9 [M.A. 7, 398].Google Scholar
Lasanlx, (A. yon), 1879. Z. Krystallogr. Mineral. 4, 172.Google Scholar
Leonhard, (K. C. yon), 1817. Tasch. Min. 11, 168.Google Scholar
Marignac, (J. C.), 1845. Ann. Phys. Chem. (Poggendorff), 132, 549.Google Scholar
Rinne, (F.), 1889, Sitzungsber. preuss. Akad. Wiss., 1027-36.Google Scholar
Walker, (G. P. L.), 1962. Mineral. Mag. 33, 187-201.Google Scholar
Winchell, (A. N.) and Winchell, (H.), 1964. Elements of optical Mineralogy, Part 2, 4th edn. Wiley, New York.Google Scholar