ALBERT

Description: 〈sec〉〈st〉Extract〈/st〉〈p〉Sir Archibald Geikie KCB, OM, FRS (1835–1924) was one of the most eminent geologists of the late 19〈sup〉th〈/sup〉 and early 20〈sup〉th〈/sup〉 centuries. Geikie was instrumental in the development of the science of geology during this period and the eminence he attained was acknowledged by the bestowal of many prestigious honours.〈/p〉 〈p〉During his distinguished career Geikie held numerous appointments, including Director-General of the Geological Survey of the United Kingdom, President of the Geological Society, President of the British Association, Trustee of the British Museum and President of the Royal Society (the only geologist to have ever held the latter honour). He was also an accomplished writer and during his career he published over 200 scientific papers, survey memoirs, books, articles and an autobiography. In addition, he was a masterful lecturer to any level of audience and a talented artist. As the most distinguished and influential geologist of the period, he received many notable honours, including a Knighthood in 1891, Knight Commander of the Bath in 1907 and the Order of Merit in 1913. In retirement Geikie continued to work vigorously as demonstrated by his contribution to the famous Geological Survey Memoir of the North West Highland of Scotland published in 1907 which he edited, his numerous obituaries of fellow geologists, geological contributions to Encyclopaedia Britannica and other publications, as well as work on his geological collections and Royal Society history.〈/p〉〈/sec〉〈p〉〈b〉...〈/b〉〈/p〉 〈p〉〈i〉This 250-word extract was created in the absence of an abstract.〈/i〉〈/p〉

Description: 〈p〉Four main depositories of Archibald Geikie material exist in the UK.〈/p〉 〈p〉〈b〉...〈/b〉〈/p〉 〈p〉〈i〉This 250-word extract was created in the absence of an abstract.〈/i〉〈/p〉

Description: 〈p〉The extensive archive of papers, illustrations, albums and specimens accumulated by Sir Archibald Geikie and held by the Haslemere Educational Museum is a rich resource for any appreciation of his professional life and achievements. This paper charts the history of the archive, highlights some of its particular treasures and discusses the key series of records it contains.〈/p〉

Description: 〈p〉The co-type and other examples of the rare mineral geikielite housed in the Natural History Museum, London are described. The history of the specimens is traced from 1892 and illustrated. A short review of geikielite is provided, together with notes on its occurrence.〈/p〉

Description: 〈p〉Fourteen previously unpublished manuscripts by Archibald Geikie are reproduced here for the first time in approximate date order. The earliest identified manuscripts date from 1847: ‘Fable One’ and ‘Frogs Desiring a King’. Geikie was only 12 years old when he wrote these compositions. Others are dated 1852, 1853 and 1857 and were all written early in Geikie's life and are very important for understanding his intellectual development at that time.〈/p〉

Description: 〈p〉The family history of Sir Archibald Geikie (1835–1924) is examined with reference to his immediate family and descendants, including much previously unpublished documentary archival material preserved at the Haslemere Educational Museum. The lives of Archibald's children are also examined. This account includes previously unpublished images of the Geikie family and gives new insights into aspects of Archibald Geikie's character through the memories of his grandson, Derick Jacob Behrens (1917–2004). Geikie's continued academic life after his retirement from the Geological Survey is discussed in relation to that institution.〈/p〉

Description: Bettertonite, [Al 6 (AsO 4 ) 3 (OH) 9 (H 2 O) 5 ]·11H 2 O and penberthycroftite, [Al 6 (AsO 4 ) 3 (OH) 9 (H 2 O) 5 ]·8H 2 O, two new minerals from the Penberthy Croft mine, Cornwall, have flexible layer structures based on corner-connected heteropolyhedral columns. Their response to dehydration on heating was studied using in situ synchrotron powder X-ray diffraction at temperatures in the range –53 to 157°C. The bettertonite sample transforms to penberthycroftite in a narrow temperature range of 67 to 97°C with a large (8%) contraction of the layer separation and a 6 Å sliding of adjacent layers relative to each other. Above 100°C a second phase transition occurs to a DL (displaced layer) phase, involving another 8% inter-layer contraction combined with a rotation of the columns. On heating the penberthycroftite sample the phase transition to the DL phase occurs at a lower temperature of ~80°C. The DL phase is stable to a temperature of ~120°C. At higher temperatures, increased rotation of the columns is accompanied by a progressive amorphization of the sample. Bettertonite, penberthycroftite and the DL phase exhibit negative thermal expansion (NTE) along all three axes with large NTE coefficients, of the order of –100 x 10 –6 °C –1 .

Description: Penberthycroftite, ideally [Al 6 (AsO 4 ) 3 (OH) 9 (H 2 O) 5 ]·8H 2 O, is a new secondary aluminium arsenate mineral from the Penberthy Croft mine, St. Hilary, Cornwall, England, UK. It occurs as tufts of white, ultrathin (sub-micrometre) rectangular laths, with lateral dimensions generally 〈 20 μm. The laths are flattened on {010} and elongated on [100]. The mineral is associated with arsenopyrite, bettertonite, bulachite, cassiterite, chalcopyrite, chamosite, goethite, liskeardite, pharmacoalumite–pharmacosiderite and quartz. Penberthycroftite is translucent with a white streak and a vitreous to pearly lustre. The calculated density is 2.18 g/cm 3 . Optically, only the lower and upper refractive indices could be measured, 1.520(1) and 1.532(1) respectively. No pleochroism was observed. Electron microprobe analyses (average of 14) with H 2 O obtained from thermogravimetric analysis and analyses normalized to 100% gave Al 2 O 3 = 31.3, Fe 2 O 3 = 0.35, As 2 O 5 = 34.1, SO 3 = 2.15 and H 2 O = 32.1. The empirical formula, based on nine metal atoms and 26 framework anions is [Al 5.96 Fe 0.04 (As 0.97 Al 0.03 O 4 ) 3 (SO 4 ) 0.26 (OH) 8.30 (H 2 O) 5.44 ](H 2 O) 7.8 , corresponding to the ideal formula [Al 6 (AsO 4 ) 3 (OH) 9 (H 2 O) 5 ]·8H 2 O. Penberthycroftite is monoclinic, space group P 2 1 / c with unit-cell dimensions (100 K): a = 7.753(2) Å, b = 24.679(5) Å, c = 15.679(3) Å and β = 94.19(3)°. The strongest lines in the powder X-ray diffraction pattern are [ d obs in Å(I) ( hkl )] 13.264(46)(011); 12.402(16)(020); 9.732(100)(021); 7.420(28)(110); 5.670(8)(130); 5.423(6)( 31). The structure of penberthycroftite was solved using synchrotron single-crystal diffraction data and refined to w R obs = 0.059 for 1639 observed ( I 〉 3( I )) reflections. Penberthycroftite has a heteropolyhedral layer structure, with the layers parallel to {010}. The layers are strongly undulating and their stacking produces large channels along [100] that are filled with water molecules. The layers are identical to those in bettertonite, but they are displaced relative to one another along [001] and [010] such that the interlayer volume is decreased markedly (by ~10%) relative to that in bettertonite, with a corresponding reduction in the interlayer water content from 11 H 2 O per formula unit (pfu) in bettertonite to 8 H 2 O pfu in penberthycroftite.

Description: Penberthycroftite, ideally [Al6(AsO4)3(OH)9(H2O)5]·8H2O, is a new secondary aluminium arsenate mineral from the Penberthy Croft mine, St. Hilary, Cornwall, England, UK. It occurs as tufts of white, ultrathin (sub-micrometre) rectangular laths, with lateral dimensions generally 〈 20 μm. The laths are flattened on {010} and elongated on [100]. The mineral is associated with arsenopyrite, bettertonite, bulachite, cassiterite, chalcopyrite, chamosite, goethite, liskeardite, pharmacoalumite–pharmacosiderite and quartz. Penberthycroftite is translucent with a white streak and a vitreous to pearly lustre. The calculated density is 2.18 g/cm3. Optically, only the lower and upper refractive indices could be measured, 1.520(1) and 1.532(1) respectively. No pleochroism was observed. Electron microprobe analyses (average of 14) with H2O obtained from thermogravimetric analysis and analyses normalized to 100% gave Al2O3 = 31.3, Fe2O3 = 0.35, As2O5 = 34.1, SO3 = 2.15 and H2O = 32.1. The empirical formula, based on nine metal atoms and 26 framework anions is [Al5.96Fe0.04(As0.97Al0.03O4)3(SO4)0.26(OH)8.30(H2O)5.44](H2O)7.8, corresponding to the ideal formula [Al6(AsO4)3(OH)9(H2O)5]·8H2O. Penberthycroftite is monoclinic, space group P21/c with unit-cell dimensions (100 K): a = 7.753(2) Å, b = 24.679(5) Å, c = 15.679(3) Å and β = 94.19(3)°. The strongest lines in the powder X-ray diffraction pattern are [dobs in Å(I) (hkl)] 13.264(46) (011); 12.402(16)(020); 9.732(100)(021); 7.420(28)(110); 5.670(8)(130); 5.423(6)(1̄31). The structure of penberthycroftite was solved using synchrotron single-crystal diffraction data and refined to wRobs = 0.059 for 1639 observed (I〉 3σ(I)) reflections. Penberthycroftite has a heteropolyhedral layer structure, with the layers parallel to {010}. The layers are strongly undulating and their stacking produces large channels along [100] that are filled with water molecules. The layers are identical to those in bettertonite, but they are displaced relative to one another along [001] and [010] such that the interlayer volume is decreased markedly (by ∼10%)relative to that in bettertonite, with a corresponding reduction in the interlayer water content from 11 H2O per formula unit (pfu) in bettertonite to 8 H2O pfu in penberthycroftite.

Description: The rare iron-tin hydroxide minerals natanite and jeanbandyite occur as small pseudo-octahedral crystals in high-temperature Sn-Cu-As veins at Penberthy Croft Mine and Hingston Downs Quarry, Cornwall. The lattice parameters for jeanbandyite and natanite are reported and compared to previously calculated values. The chemical composition of jeanbandyite is discussed and a significant proportion of divalent Fe and Mn is shown to be present.