Where it forms, where it's found
- Geological setting
Late-stage veinlets in copper-sulphide ores hosted in layered hedenbergite-andradite-actinolite skarn. Highly oxidizing environment from low-temperature Fe-rich fluids and crystallized in cavities and fractures within the skarn-ore deposit.
- Type locality
- Saishitang Mine (Saishentang Mine
- Sashitang Mine)
- Xinghai County
- Hainan
- Qinghai
- China
35.3072°, 99.7886°
Physical
Optical
- Refractive index
- 1.592 – 1.628
- Surface relief
- Moderate
- Principal indices
- nα 1.592 – 1.620 · nγ 1.628
- Pleochroism
- Strong
Light red-brown (for light vibrating perpendicular to the fiber axis) to dark red-brown (for light vibrating parallel to the fiber axis.
- Notes
Z || c, X (or Y) || a No data given on which optical or crystallographic direction is parallel to fibers elongation.
Crystallography
- Cell parameters
- a = 13.467(16) Å · b = 26.953(41) Å · c = 5.226(17) Å
- Ratio a:b:c
- 1 : 2.001 : 0.388
- Type-locality form
Brown earthy and fibrous aggregates with an appearance of wood bark, consisting of fibrous crystals several micrometers wide and several centimeters long. Also as brown earthy mass consisting of individual grains of flaky-acicular microlites with poor crystallinity, a few micrometers or less in size.
- Comment
Space group Pncn.
Chemical composition
Synonyms
- Ferrisepioliet
- IMA2010-061
In other languages
- German
- Ferrisepiolith · IMA 2010-061
- Italian
- ferrisepiolite
Classification
9.00
- 9SilicatesClass
- 9.0— unnamed intermediate level —Division
- 9.00— unnamed intermediate level —Group
- 9.00FerrisepioliteSpecies
Group, growth & confusion
Literature, links & citation
- 2011Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2011) New minerals and nomenclature modifications approved in 2010, CNMNC Newsletter No 7. Mineralogical Magazine, 75 (1) 27-31 doi:10.1180/minmag.2011.075.1.27 DOI: 10.1180/minmag.2011.075.1.27
- 2013Xiangping, Gu, Xiande, Xie, Xiangbin, Wu, Guchang, Zhu, Jianqing, Lai, Kenich, Hoshino, Jiwu, Huang (2013) Ferrisepiolite: a new mineral from Saishitang copper skarn deposit in Xinghai County, Qinghai Province, China. European Journal of Mineralogy, 25 (2) 177-186 doi:10.1127/0935-1221/2013/0025-2262DOI: 10.1127/0935-1221/2013/0025-2262
- 2015(2015) Ferrisepiolite. Handbook of Mineralogy. Mineralogical Society of America
@misc{mineral2026,
author = {Mineral Index editorial board},
title = {Ferrisepiolite — Mineral Index},
year = {2026},
url = {https://mineralindex.org/minerals/ferrisepiolite-41139},
note = {Accessed 2026-05-11}
}