Work

Zincostottite, ZnGe(OH)6, the zinc analogue of stottite from Tsumeb, Namibia

Year: 2024

Type: article

Abstract: The new mineral zincostottite (IMA2024-024), ZnGe(OH)6, was found on specimens from the Tsumeb mine, Tsumeb, Namibia, where it is a secondary oxidation-zone mineral. It occurs as heavily etched remnants of equant or tabular crystals, up to ∼1 mm in diameter. Crystals are colourless and transparent, with vitreous to subadamantine lustre and a white streak. The mineral is brittle with irregular stepped fracture. The Mohs hardness is ∼4.5. Cleavage is good on {100} and poor on {001}. The calculated density is 3.834 g·cm–3. Optically, zincostottite is uniaxial (–) with ω = 1.785(5) and ε = 1.765(5) (white light). The empirical formula is (Zn0.77Fe3+0.23)Σ1.00Ge1.00O6H5.77. Zincostottite is tetragonal, space group P42/n, with cell parameters: a = 7.4522(18), c = 7.4000(8) Å, V = 411.0(2) Å3 and Z = 4. The crystal structure (R1 = 2.65% for 452 I > 2σ I reflections) is the same as that of stottite with Zn in place of Fe2+

Source: Mineralogical Magazine

DOI: 10.1180/mgm.2024.81

Authors: Anthony R. Kampf, Joy Désor, Mark D. Welch, Chi Ma, Gerhard Möhn

Institutions: Natural History Museum of Los Angeles County, Natural History Museum, California Institute of Technology

Language: English

Topic: Mineralogy and Gemology Studies

Subfield: Geochemistry and Petrology

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: bronze

Funders: National Science Foundation, California Institute of Technology

Award: MRI: Acquisition of a field emission electron microprobe for Caltech Division of Geological and Planetary Sciences