Ejected blocks of piutonic igneous facies have long been known in the trachytic and basaltic tufts of Green Mountain and Middleton Peak on Ascension Island, and a petrographic account of them has been recorded by Professor R. A. Daly in his memoir on the geology of Ascension Island.
Die Fällung von CaCl2MgCl2‐Lösung führt bei einem molaren Verhältnis Mg:Ca ∼ 5:1, also bei Neutralsalzüberschuß, nie zu Dolomit, sondern nur zur Bildung von Calciumcarbonatmonohydrat CaCO3 · H2O. Das Nichtauftreten von Dolomit steht im Einklang mit der Annahme, daß die Lage des Hydratationsgleichgewichtes der Mg2+‐Ionen die Ausbildung eines Gitters mit anhydrischen Mg2+‐Ionen verhindert.
SummaryDrugmanite occurs as rare colourless transparent platy crystals, up to 0.2 mm, aggregated in bunches, in vugs of a mineralized and silicified limestone. Hardness < 6. Crystals monoclinic, forms {001} {110}, parameters from indexed X-ray powder pattern (and monocrystal measurements): a = 11.110 (11.111) Å, b = 7.976 (7.986), c = 4.644 (4.643), β = 90°18′ (90°.41°). Space group P21/a with Z = 2 giving Dcalc = 5.55. Strongest lines are 4.63 Å (9), 3.752 (IO), 3.350 (8), 3.247 (8), 2.912 (9). Mean refractive index 1.88 from reflectance measurements. Strong dispersion r < v, optic axial plane // (olo), 2Vα = 33±2°. Electron microprobe analysis gave P 8.89, Al 0.85, Fe 6.19, Pb 59.76%, leading to Pb4.02 Al0.45)P4.00O17.02·3H2O or Pb2 (Al0.22) (PO4)2 (OH)·H2O. Associated minerals are pyromorphite, anglesite, corkite and phosphosiderite. Named for J. Drugman, Belgian mineralogist (1875–1950).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.