| Abstract: | Zimbabweite occurs as honey yellow-brown crystals (= or <1 X 1 X 2 cm) in kaolinized granite pegmatite and dump material at St Anns mine, Karoi (formerly Urungwe) district. It is clear pale yellow in thin fragments and has one excellent cleavage (010), H. 5-51/2, adamantine lustre, non-magnetic, D 6.20 g/cm3; optically biaxial, all refr. ind. > 2.10, 2Vgamma approx 80o, dispersion very strong v > r; alpha (pale yellow brown) = c, beta (light reddish brown = b, gamma (reddish brown) = a. Mean reflectance in air for an (010) = alpha -gamma cleavage plate is 16.6% at 589 nm. Chemical analysis gave Ta2O5 46.5, As2O3 26.5, PbO 15.0, Nb2O5 4.8, Na2O 3.1 K2O 1.5, TiO2 1.4, BaO 0.4, UO2 0.3, Bi2O3 0.2, H2O 0.19, SnO2 0.1, F 0.04, SrO 0.02, less O = F 0.02, = 100.05, leading to the idealized formula (Na,K)2PbAs4(Ta,Nb,Ti)4O18. Indexed XRD powder data are tabulated; strongest lines 3.195(100), 2.990(70), 2.882(70), 3.033(60), 3.823(55), 2.548(50), 1.913(50) A; a 12.233, b 15.292, c 8.665; A; space group Ccma or Cc2a, Z = 4. The TG curve shows a rapid weight loss of approx 22.5% at 840-900oC, due to the loss of As2O5.-R.A.H. |
| Genre: | Article |
| ProdID: | 70014536 |
| Citation Author: | Foord, E. E.; Taggart, J. E.; Gaines, R. V.; Grubb, P. L. C.; Kristiansen, R. |
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| Citation End Page: | 336 |
| Citation Issue: | 4 |
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| Citation Language: | English |
| Citation Larger Work Title: | Bulletin de Mineralogie |
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| Citation Number Of Pages: | 6 |
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| Citation Search Results Text: | Zimbabweite, a new alkali-lead arsenic tantalate from St Anns mine, Karoi district, Zimbabwe.; 1986; Article; Journal; Bulletin de Mineralogie; Foord, E. E.; Taggart, J. E.; Gaines, R. V.; Grubb, P. L. C.; Kristiansen, R. |
| Citation Start Page: | 331 |
| Citation Volume: | 109 |
| Citation Year: | 1986 |
| Type: | citation/reference |
| Text: | Zimbabweite, a new alkali-lead arsenic tantalate from St Anns mine, Karoi district, Zimbabwe.; 1986; Article; Journal; Bulletin de Mineralogie; Foord, E. E.; Taggart, J. E.; Gaines, R. V.; Grubb, P. L. C.; Kristiansen, R. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Wed, 1 Jan 1986 00:00 -0600 |
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