Serpierite

Serpierite

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General
Category	Mineral

Occurrence

new article content ... 31.06.02.01 Serpierite Ca(Cu,Zn)4(SO4)2(OH)6•3H2O (IMA) Devilline Group, members Aldridgeite, Campigliaite, Devilline, Kobyashevite, Lautenthalite, Unnamed (Dimorph of Devilline) (Mindat) Ca-analogue of aldridgeite (Cd,Ca)(Cu,Zn)4(SO4)2(OH)6•3H2O (Mindat) Dimorphous with orthoserpierite (All) Formula: Ca(Cu,Zn)4(SO4)2(OH)6•3H2O (IMA) Molar Mass: 644.32 g (Webmin) Density (calculated): 3.08 g/cm (AM54,All) Dana: 31 : hydrated sulphates containing hydroxyl or halogen Strunz: 6/D.19-20 or 7.DD.30 Year of Discovery: 1881. Named in that year by Alfred Lewis Oliver Legrand Des Cloizeaux in honor of Giovanni Battista Serpieri [March 23, 1832 Rimini, Italia - October 17, 1897 Athens, Greece], revolutionary, engineer, Italian mining entrepreneur, and a developer of mines in the Lavrion District, Attiki, Greece (Mindat). Founder of the Montecatini Company (Dana) Crystal Class: Monoclinic 2/m, space group C2/c (AM54, All), pseudo-orthorhombic (HOM) Structure: Isostructural with: Aldridgeite (Mindat) Unit Cell Parameters a = 22.186Å, b = 6.250Å, c = 21.853Å β = 113.37° Z:8 (Mindat, Dana, Webmin)) a = 22.186Å, b = 6.250Å, c = 21.853Å β = 113.37° Z:1 (AM54) a= 22.186(2) Å, b= 6.250(2) Å, c= 21.853(2) Å, β= 113.36(1) °, Z=8 (HOM) Crystal habits: crusts and tufted aggregates of tiny lathlike crystals, botryoidal (All). Platy varieties are visually indistinguishable from orthoserpierite (Mindat). Morphology: Lathlike crystals are elongated along [010], flattened on {100}, with {10B1}, {31B1}, {B311} (HOM) Lathlike crystals are elongated [100] and flattened {001} (MM, Dana, Mindat) Colour: Sky blue (All), greenish blue in transmitted light (Mindat, HOM) Greenish-blue (MM) Streak: White or pale blue (Mindat), greenish white (Webmin) Lustre: Vitreous, pearly on cleavages (All) Diaphaneity: Transparent (All except Dana, which omits diaphaneity) Optic Class: Biaxial (-) (MM, All) Refractive Indices: nα = 1.584, nβ = 1.642, nγ = 1.647 (Dana) nα = 1.583, nβ = 1.641, nγ = 1.648 (USGS, AM54, Mindat) nα = 1.583-1.584, nβ = 1.641-1.642, nγ = 1.647-1.648 (Webmin) nα = 1.584(3), nβ = 1.642(3), nγ = 1.647(3) (HOM) Maximum birefringence δ = 0.065 (USGS, Mindat), 0.0640 (Webmin) 2V: Measured: 33° to 37° (Dana, Mindat), 35 (Webmin, HOM) 2V: Calculated: 37o (AM54), 36° (Mindat), 34 (Webmin), 37 (HOM) 37 +/- 6 (USGS) Dispersion of the optic axes r> v, strong (USGS, Dana, HOM) Surface Relief: Moderate (Mindat) Orientation Y = b; X∧a = 24◦; Z ~ c (AM54, HOM) Y = b; X^a =24; Z = c (Dana) X = c; Y = a; Z = b (Mindat) Y = b; X^a =24 (USGS) Pleochroism: X = pale green; Y = bluish green; Z = blue green (AM54) X = pale green; Y = bluish green; Z = bluish green (USGS, Dana, Webmin) X = Nearly colourless; Y = Deep greenish blue; Z = Deep greenish blue (Mindat) X = nearly colorless, pale green; Y= bluish green; Z= deep greenish blue, blue-green (HOM) Cleavage: Perfect on {001} (Dana, Mindat, Webmin) Perfect on {100} (USGS, HOM) Fracture: Splintery (Mindat) Tenacity: Brittle (Mindat) Hardness: 2 (Mindat), 3.5 – 4 (Webmin), not defined (HOM) Specific Gravity: 3.07 (USGS, AM54, All) Solubility: soluble in acids. (USGS, Dana, Mindat) Other Characteristics: Serpierite is not radioactive (Webmin) Type Locality: Serpieri Mine, Kamariza Mines (Kamareza Mines), Agios Konstantinos [St Constantine] (Kamariza), Lavrion District Mines, Lavrion District (Laurion; Laurium), Attikí Prefecture (Attica; Attika), Greece (Mindat) Type Material: Natural History Museum, Paris, France, 73.38, 78.226 (HOM) Associated Mineral at the type locality: Smithsonite (Mindat) Occurrence and Associations: Secondary mineral found in altered smelter slags and oxidized sulphide veins (Webmin) A secondary mineral in the oxidized zone of hydrothermal Cu–Zn-bearing hydrothermal mineral deposits; commonly a post-mine product (HOM) Associations: Smithsonite, devilline, posnjakite, ktenasite, linarite, langite, brochantite,wroewolfeite, namuwite, schulenbergite, hydrozincite, malachite, gypsum (HOM). Localities • Old copper mine of Ross Island, Killarney, County Kerry, Ireland. Ores are chalcopyrite, tetrahedrite and bornite, which occur together with calcite in a thin bed of bluish- grey Carboniferous limestone. There also occurred rarely native copper, cuprite, malachite and chessylite. Specimens of serpierite were obtained from dump debris from a large water-logged hole called the Blue Hole at the eastern end of the workings. The ores worked in the Blue Hole were sphalerite, galena, pyrite and chalcopyrite. Smithsonite is “tolerably abundant” (MM). • Brownley Hill Mine, Cumbria, England. Serpierite occurs with harmotome, gypsum and rarely with brochantite in fractures in the quartz lining of a large cavity on Brownley Hill vein at Brownley Hill Mine. The aggregates of blue lathlike crystals reach about 2 mm and appear to have been produced by post-mining oxidation of chalcopyrite. • Acicular serpierite crystals to 1 mm were discovered at Neudorf in the Harz Mountains Germany by Schnorrer in 2004, in samples from dumps provided by Rolf Junker who described several post-mining minerals in 1991. According to Schnorrer serpierite occurs as leafy pale blue iridescent crystals overgrown by gypsum and by hedgehog-shaped aggregates of aragonite crystals (Minrec43). • Scatterings of sky blue serpierite needles have been collected in dump material from the Kintore and block 14 open cuts, Broken Hill, New South Wales, Australia. Matted crusts and hemispherical sprays of delicate needles to 0.5 mm, with a silky lustre. Sometimes groups of blocky prisms to 0.3 mm or sword shaped blades to 0.5 mm long. The most commonly associated sulphate minerals are schulenbergate and brochantite, with antlerite, ktenasite, and linarite less abundant. The host rock is often corroded quartz containing patches of sphalerite, cuprite or native copper, but serpierite has been found on fractures in barren host rock gneisses. Microprobe analysis shows that serpierite contains appreciable zinc (AJM3). • At the Lloyd copper mine at Burraga New South Wales, Australia just below the entrance to the main inclined shaft, an open adit drains water affected by acid mine drainage from the upper levels of the open workings. Serpierite and langite together with other species coat the bed of the water course and continue into a small gully nearby (AJM10). • At the Tynebottom Mine, Garrigill, Cumbria, zoned iron and copper post-mining oxidation deposits have been found in a pile of waste rock. The inner part of each individual deposit usually consists of iron minerals such as limonite and jarosite with some gypsum derived from the oxidation of pyrite and chalcopyrite in the rock matrix. This 'iron zone' is then surrounded by a rim of copper based minerals, the most common sequence being brochantite, leading in to serpierite and devilline and finishing with malachite. Other minerals occurring in this zone include linarite, anglesite, cerussite, wroewolfeitel. Beyond the rim of copper based minerals the matrix is usually at least partly covered with flowstone calcite or tufts of aragonite or quite commonly both, as well as other carbonates such as brianyoungite and hydrozincite. Visually the serpierite consists of pale turquoise-blue radiating usually flat crusts of feathery needles with a silky lustre. Individual crystals are no more than 0.5 mm long (JRS10). • Serpierite is extremely rare at Red Gill, Cumbria, England, where it was reported by Cooper and Stanley in as soft, pale blue micaceous aggregates on cerussite. It is probably a dump formed mineral (JRS11).

References USGS: Larsen, E.S. (1921) The Microscopic Determination of the Nonopaque Minerals, First edition, USGS Bulletin 679:253 AK: Goldschmidt, V. (1922) Atlas der Krystallformen, volume 8 page 37 MM: Russell (1927) Mineralogical Magazine 21: 386 AM54: American Mineralogist (1969) 54:328-329 abstracted from Faraone, D., C. Sabelli, and P.F. Zanazzi (1967) Su du solfati basici idrati: serpierite e devillite. Atti Rend. Accad. Lincei, 43, 369–382 (in Italian with English abstract) Dana: Gaines et al (1997) Dana’s New Mineralogy, Eighth Edition. Wiley AJM3: Australian Journal of Mineralogy (1997) 3-1:44-45 Minrec31: Mineralogical Record (2000) 31-3:247 AJM10: Australian Journal of Mineralogy (2004) 10-1:3 JRS10: Journal of the Russell Society (2007) 3:9 JRS11: Journal of the Russell Society (2008) 11:42 Mindat: http://www.mindat.org/min-3625.html Webmin: http://www.webmineral.com/data/Serpierite.shtml#.VFMoXBbgXld HOM: http://www.handbookofmineralogy.org

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