Where it forms, where it's found
- Geological setting
Very fine-grained aggregates in vugs of massive renierite – germanite – tennantite ore
- Type locality
- Tsumeb Mine (Ongopolo Mine)
- Tsumeb
- Oshikoto Region
- Namibia
-19.2270°, 17.7276°
1recorded occurrences
Physical
Optical
- Optical type
- Biaxial (+)
- Pleochroism
- Non-pleochroic
- Anisotropism
- moderate
- Tropism
- Anisotropic
Crystallography
- Cell parameters
- a = 8.302 Å · b = 9.718 Å · c = 4.527 Å
- Ratio a:b:c
- 1 : 1.171 : 0.545
- Unit cell volume
- 365.2 ų
- Z
- 2
- Morphology
The type material shows the following forms: (100) major, very thin (010), rounded (011), and very thin rounded (001) minor. Crystals show growth steps on (100) and are partly hollow.
- Type-locality form
Individual subhedral to (rare) euhedral crystals are platy to very thin prismatic, elongate [001], with a length-to-width ratio of approximately 3:1 and not exceeding 20 µm in maximum length. Typical crystals are 20 × 14 × 1 µm in size.
- Comment
Point Group: n.d.; Space Group: n.d. (P lattice) a
Chemical composition
Synonyms
- Eyseliet
- IMA2003-052
In other languages
- German
- Eyselit · IMA 2003-052
- Italian
- Eyselite
Classification
Strunz
10th ed.4.DM.20
- 4OxidesClass
- 4.DMetal: Oxygen = 1:2 and similarDivision
- 4.DMWith large (+- medium-sized) cations; unclassifiedGroup
- 4.DM.20EyseliteSpecies
Literature, links & citation
Citations
- 2004Roberts, A. C., Seward, T. M., Reusser, E., Carpenter, G. J.C., Grice, J. D., Clark, S. M., Marcus, M. A. (2004) Eyselite, Fe3+Ge4+3O7(OH), a new mineral species from Tsumeb, Namibia. The Canadian Mineralogist, 42 (6) 1771-1776 doi:10.2113/gscanmin.42.6.1771 DOI: 10.2113/gscanmin.42.6.1771
- 2014(2014) Eyselite. Handbook of Mineralogy. Mineralogical Society of America
Cite this entry
@misc{mineral2026,
author = {Mineral Index editorial board},
title = {Eyselite — Mineral Index},
year = {2026},
url = {https://mineralindex.org/minerals/eyselite-27221},
note = {Accessed 2026-05-11}
}