Wooldridgeite, Na₂(P₂O₇)₂(H₂O)₁₀: A new mineral from Judkins Quarry, Warwickshire, England

Abstract

Wooldridgeite, ideally Na2(P2O7)2(H2O)10, orthorhombic, a = 11.938(1), b = 32.854(2), c = 11.017(1) Å , V = 4321.2(8) Å3, a:b:c = 0.3634:1:0.3353, space group Fdd2, Z = 8, is a new mineral from Judkins Quarry, Nuneaton, Warwickshire, England. Associated minerals are calcite, chalcopyrite, bornite and baryte. It occurs as equant crystals forming rhombic dipyramids; no twinning was observed. It is transparent blue-green with a very pale-blue streak, a vitreous lustre, and does not fluoresce under long- or short-wave ultraviolet light. Wooldridgeite has a Mohs hardness of 2–3, is brittle with an irregular fracture, and has no cleavage. The calculated density is 2.279 g/cm3. In transmitted light, wooldridgeite is colourless, non-pleochroic, and shows no dispersion. It is biaxial negative with α = 1.508(1), β = 1.511(1), γ = 1.517(1), 2V(meas.) = 76.2(5), 2V(calc.) = 71(10)8, X = b, Y = c, Z = a. The strongest five reflections in the X-ray powder diffraction pattern are [d(Å), (I), (hkl)]: 8.23(30)(040), 6.52(100)(131), 4.05(40)(260), 3.255(40)(262); 2.924(40)(371). Electron-microprobe analysis of wooldridgeite gave P2O5 39.37, CuO 20.24, MgO 0.24, CaO 7.73, Na2O 8.33, K2O 0.17, H2O(calc.) 24.72, sum 100.80 wt.%; the corresponding unit formula (based on 24 anions) is (Na1.96K0.03)Ca1.00(Cu1.85Mg0.04)P4.04O14(H2O)10 where the H2O groups were assigned from knowledge of the crystal structure; the infrared absorption spectrum also indicates the presence of H2O in the structure. The mineral is named for James Wooldridge (1923–1995), a fervent amateur mineral collector who discovered this mineral.

Links Between Hydrothermal Environments, Pyrophosphate, Na+, and Early Evolution

“…However, the first occurrence of a natural pyrophosphate mineral, canaphite, was reported in the scientific literature only in 1985 (Peacor et al 1985; Rouse et al 1988), and the second, wooldridgeite, in 1999 (Hawthorne et al 1999). The canaphite specimens were found on zeolite crystals (stilbite) in cavities of Triassic trap rock (basalt) from New Jersey, USA, whereas wooldrigeite was found in an unconformity between Precambrian igneous rocks and overlying Cambrian sedimentary rocks.…”

Glasses as sources of condensed phosphates on the early earth

“…The first occurrence on Earth of a natural pyrophosphate mineral, canaphite, was not reported in the scientific literature until 1985 [44,45]. The second mineral, wooldridgeite, was discovered in 1999 [46]. The canaphite was found on crystals of the zeolite mineral stilbite in cavities of Triassic basalts in New Jersey, USA, whereas wooldridgeite was found in an unconformity between Precambrian igneous rocks and overlying Cambrian sedimentary rocks in Warwickshire, England.…”

Hylbrownite, Na3MgP3O10·12H2O, a new triphosphate mineral from the Dome Rock Mine, South Australia: description and crystal structure

“…Unit-cell parameters for these compounds were refined from powder X-ray diffraction data (Table 8), however, they were not characterized structurally. Hylbrownite is the fourth example of a condensed phosphate mineral after kanonerovite (Popova et al, 2002), and the pyrophosphates canaphite CaNa 2 P 2 O 7 •4H 2 O (Peacor et al, 1985;Rouse et al, 1988) and wooldridgeite Na 2 CaCu 22 (P 2 O 7 ) 2 •10H 2 O (Hawthorne et al, 1999;Cooper and Hawthorne, 1999). Hylbrownite is the third known phosphate of Na and Mg, after panethite, (Na,Ca,K) 4 (Mg,Fe 2+ ,Mn) 4 (PO 4 ) 2 , (Fuchs et al, 1967) and bakhchisaraitsevite, [Na 2 (H 2 O) 2 ] {(Mg,Fe) 5 (H 2 O) 5 (PO 4 ) 4 } (Liferovich et al, 2000;Yakubovich et al, 2000).…”