Where it forms, where it's found
- Geological setting
Former Cu mine; in crevices of Mn ore containing native copper, as a result of reaction of seawater with the ore.
- Type locality
- Ohku mine
- Ikata (Sadamisaki Peninsula)
- Nishiuwa District
- Ehime Prefecture
- Japan
33.4117°, 132.1811°
Physical
Crystallography
- Space group
- P21/m
- Cell parameters
- a = 5.717(2) Å · b = 6.586(2) Å · c = 5.623(3) Å
- Cell angles
- β = 88.45(3) °
- Ratio a:b:c
- 1 : 1.152 : 0.984
- Unit cell volume
- 211.63 ų
- Morphology
Radial and dendritic aggregates consisting of pale green, bladed crystals.
- Type-locality form
Blades, in radial and dendritic aggregates
- Comment
"same axial setting with botallackite"
Chemical composition
Synonyms
- IMA2013-130
- Iyoiet
In other languages
- German
- IMA 2013-130 · Iyoit
- Italian
- iyoite
Classification
3.DA.10b
- 3HalidesClass
- 3.DOxyhalides, hydroxyhalides and related double halidesDivision
- 3.DAWith Cu, etc., without PbGroup
- 3.DA.10bIyoiteSpecies
Group, growth & confusion
AtacamiteCu2Cl(OH)3Mineral—
BotallackiteCu2Cl(OH)3Mineral—
ClinoatacamiteCu2Cl(OH)3Mineral—
GillarditeCu3NiCl2(OH)6Mineral—
HaydeeiteCu3Mg(OH)6Cl2Mineral—
HerbertsmithiteCu3Zn(OH)6Cl2Mineral—
HibbingiteFe2+2(OH)3ClMineral—
KapellasiteCu3Zn(OH)6Cl2Mineral—
KempiteMn2+2Cl(OH)3Mineral—- KuliginiteFe3Mg(OH)6Cl2Mineral—
Literature, links & citation
- 2014Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2014) New minerals and nomenclature modifications approved in 2014, CNMNC Newsletter No 20. Mineralogical Magazine, 78 (3) 549-558 doi:10.1180/minmag.2014.078.3.05DOI: 10.1180/minmag.2014.078.3.05
- 2017(2017) Iyoite. Handbook of Mineralogy. Mineralogical Society of America
- 2017Nishio–Hamane, D., Momma, K., Ohnishi, M., Shimobayashi, N., Miyawaki, R., Tomita, N., Okuma, R., Kampf, A. R., Minakawa, T. (2017) Iyoite, MnCuCl(OH)3 and misakiite, Cu3Mn(OH)6Cl2: new members of the atacamite family from Sadamisaki Peninsula, Ehime Prefecture, Japan. Mineralogical Magazine, 81 (3) 485-498 doi:10.1180/minmag.2016.080.104 DOI: 10.1180/minmag.2016.080.104
@misc{mineral2026,
author = {Mineral Index editorial board},
title = {Iyoite — Mineral Index},
year = {2026},
url = {https://mineralindex.org/minerals/iyoite-45980},
note = {Accessed 2026-05-11}
}