IN the course of a continuing review of rare minerals that have been reported from the British Isles, we have examined Cornish specimens that purported to be the bismuth silicate, eulytine (Collins, 1881). Two localities are involved: the Restormel (also Royal) iron mine, near Lostwithiel, noted for its remarkable goethite crystals; and Wheal Coates, St Agnes, best known for its pseudomorphs of cassiterite after orthoclase. Collins' specimens, one from each locality (nos. 1588 and 1589, respectively), are in the mineral collection of the Royal Institution of Cornwall, Truro; and another Restormel specimen (BM 32875, Talling no. 614) is in that of the British Museum (Natural History). Specimens from both localities are rather unprepossessing, showing some 'bismuth ochre'. Only on the Restormel material are there a few small, shining crystals, which have proved to be waylandite, a member of the crandallite group; but we have found no eulytine (Macpherson, 1983, p. 249). The dealer Richard Talling, who supplied the BM specimen in 1861, invoiced the crystals as being 'bismuth blende' (= eulytine) and thus seems to be responsible for the original identification, presumably on the basis of appearance and association. A second Talling specimen was acquired as bismutite with the Russell collection (BM 1964R, 7185), and the exact fit of its broken surface shows that if is the 'other half' of BM 32875. It bears the printed number 765, with solid lines above and below, in contrast with the handwritten no. 614; and it is instructive to note that Talling used written numbers for the best specimens he sold, with a different sequence of printed ones for those that he considered less good. The Wheal Coates specimen (RIC no. 1589) has neither waylandite nor eulytine on it, and the earthy mineral gives a clear X-ray powder pattern of bismutite, the basic carbonate of bismuth. Similar material was first examined by the Revd W. Gregor, in about 1809, who supplied the specimen described as an earthy steatite-like mineral and figured in Sowerby's British Mineralogy (Vol. IV, 1811). The status of this material as a carbonate was doubted by Beudant (1832), and later by Greg and Lettsom (1858), but was accepted by Brooke and Miller (1852) who named it agnesite for the locality. It would seem that Gregor (misnamed 'Macgregor'

S.W. 7 SUM MARY. Previous investigations have been confined to individual members or to small compositional ranges of the amblygonite-montebrasite series. The present study is a survey based on twentytwo specimens in the range Amb~Monso to Amb~o.Mon8 (i.8-11.8 % fluorine), and indicates that the fluorine content may be related both qualitatively and quantitatively to differences in the X-ray powder patterns. Fully indexed powder data to d ~ 1.68 ,~ and derived cell parameters are given for four members of the series. There is no evidence of a break in the continuity of the series. The first British occurrence of both amblygonite and montebrasite is reported from a pegmatite vein in aplite at Meldon, Okehampton, Devonshire.I Y the course of an examination of a number of specimens of presumed amblygonite and montebrasite collected by the late Mr. A. W. G. Kingsbury at the old aplite quarry, Meldon, Devonshire, we noted marked differences between the X-ray powder patterns. It was by no means clear from published data that all the specimens belonged to the series, and variations in powder patterns of different specimens of montebrasite (Quensel, 196z ) were less than we observed. Other workers (Fisher, I958; Kittrick and Hope, I967) distinguish between amblygonite and montebrasite on the basis of spacing and intensity differences of the three strongest lines of the patterns, and on comparisons of single crystal diffraction patterns with powder patterns, but their reference samples are inadequately characterized and their data too scanty. The powder patterns figured by Pough and Henderson (1945) are indistinct, and are not supported by chemical analyses. Twenty-two specimens of amblygonite and montebrasite were selected for apparent homogeneity, and powder prepared from each was used for partial chemical analysis (table l) and both photographic and diffractometer records of the powder patterns. Careful examination of the photographic powder patterns showed that it is possible to distinguish four general types of pattern, here designated A, AB, B, and C ( fig. l). Diffractometer records, mentioned below, permit division of the AB pattern-type into two ( fig. z).For chemical analysis, between 15 and 7o mg of the powder were fused with five times their weight of sodium carbonate, extracted with 4o ml of I : I sulphuric acid, transferred to a distillation flask, and the fluorine steam-distilled. Fluorine was determined on the distillate by the zirconium-eriochrome-cyanine method of Megregian (t954). Alkalis were determined by flame photometry on a sulphuric acid solution.Comparison of the chemical and X-ray results shows that there is a correlation between pattern-type and fluorine content ( fig. 4)-The replacement of lithia by soda

Hexagonal (Ln, CaH)Cu6(AsO4)a(OH)6.3H20 Pale-green fibres, resembling aurichalcite and giving the powder-pattern of mixite (q.v.), on mimetite in quartz on old specimens in the BM(NH), at Wheal Alfred, Phillack, Cornwall. The variety agardite-(Nd), according to F. Permingeat, priv. comm. Akermanite Ca2(MgSi, Al2) SiO: Tetragonal Small coloudess or faintly brown crystals in thermally altered limestone at Kilchoan, Ardnamurchan, Argyllshire, Scotland. S. O. Agrell (1965), Mineral. Mag. 34, 2. Algodonite near Cu6As Orthorhombic R. K. Harrison (I973). See under maucherite. 2 Consider, for example, the entries in M. Fleischer's 'Glossary of Mineral Species' (1975). ~) Copyright the Mineralogical Society 17o Alunite KA13(SO4)2(OH)6 Rhombohedral Small eolourless rhombs and white massive from a vein in a dolerite sill at Embleton quarry, near Cockermouth, Cumberland. A. W. G. Kingsbury (I955), Mineral. Mag. 32, 4x8. **Amalgam Hg-Ag alloy Cubic Thin dull brassy sheets on grey baryte, with tennantite in limestone, at Gortdrum mine, Oola, Co. Tipperary, Ireland. BM(NH) specimens, collected by A. J. Criddle and G. S. Bearne, I974. Amblygonite (Li, Na)A1PO4(F, OH) Triclinic See under montebrasite. Also, in leucogranite near the roof of the Tregonning granite, Rinsey, Cornwall. C. S. Exley and M. Stone (x964), in 'Present views of some aspects of the geology of Cornwall and Devon' (Roy. geol. Soe. Cornwall), pp. I44-5, Anglesite (var. radian anglesite) Small (< o.I ram) white crystals of anglesite in uraniferous hydrocarbon at Wheal Speed, Cornwall, contain co-precipitated radium. Other localities for radium concentrations are given. R. K. Harrison and K. Taylor (I966), Bull. geol. Surv. Gt. Britain, 25, 4 I. * * Ardennite Orthorhombic Complex arsenate-vanadate-silicate of Mn, AI, etc. Orange-brown cleavages on vein quartz, at Merehead quarry, near Shepton Mallet, Somerset. Specimen found by C. Parkinson (1977) and given to BM(NH). Argentojarosite Rhombohedral AgF%(SO4XOH)6 Yellow, micaceous, and ochreous, at West Turf Pits mine, Grassington Moor, Yorkshire. Also, at Treore mine, St. Teath, Cornwall. A. W. G. Kingsbury (I964), Mineral. Mag. 35, li; idem (I964), in 'Present views of some aspects of the geology of Cornwall and Devon' (Roy. geol. Soc. Cornwall), p. 249. Arthurite Monoclinic near CuFe2(AsO4)2(O, OH)2.4H20 Thin apple-green crusts, alone or with pharmacosiderite or a hidalgoite-like mineral or both, on quartzose matrix at Hingston Down Consols,

SummaryConfusion over the status of crichtonite is due to the fact that de Bournon included two different minerals in his species: thin hexagonal plates are indeed ilmenite, as has been generally assumed, but the much rarer steep rhombohedra with basal plane are a separate species, with a distinctive X-ray powder pattern (three strongest lines: 3·39 Å,s; 2·875,s; 2·131,S) and a composition (Fe2+,Fe3+,Ti)1·71O3 with Fe2+:Fe3+:Ti near 8:7:33. There is a rhombohedral pseudo-cell containing three oxygens, with α 23° 19′, a 7·117 Å but there is some evidence of twinning, and the true symmetry is probably orthorhombic or lower.

S in c e the cumulative total o f names in the 28 Lists has now passed 5000-the exact number being difficult to determine because many are mentioned en passant (cf. expandite, this List)-it seems an appropriate moment to restate their objective. The introductory note to the 1st List {Min. Mag. II-323 (1897)) started 'The following is a list of recently published names, which are not to be found in the 6th edition (1892) o f Dana's System o f Mineralogy. Although it can scarcely be hoped to make such a list complete, it may still be useful for reference.' Spencer extended the scope somewhat with the 2nd List: 'In addition to names which have recently been published are a few earlier names which are not be found in some o f the larger works of reference' ; and by the 5th List he was able to say, 'In the present list are included several trivial names which have been recently applied for trade purposes to the cheaper gem-stones. Although such names are here listed alphabetically for convenience of reference, it is to be hoped that they will not find their way into mineralogical literature' (cf. Min. Mag. 23-624, footnote). It will be seen, therefore, that our inclusion of a distressingly large number o f deplorably trivial trade names is in the interest o f reference, and does not constitute a departure from precedent. We hope that they may serve as a guide and a warning to authors in the throes o f coining names for genuinely new species. We assume, with regret, that it is beyond anyone's powers to control the flow o f mineral-sounding names from commerce, but we could wish that editors o f lapidary and hobby periodicals would exercise some form o f censorship (particularly in respect o f the seemingly endless varietal names for dirty quartz and chalcedony). A n unnecessary name for aluminian lizardite, from the Lake Superior region. Cf. Al-antigorite, this List.