Ferriandrosite-(La)

Where it forms, where it's found

Geological setting: Tephroite ± calcite veinlets cutting a stratiform ferromanganese deposit.
Type locality: Shobu manganese deposit
Shobu
Ise City
Mie Prefecture
Japan

Crystallography

Crystal system: Monoclinic
Space group: P21/m
Cell parameters: a = 8.8779(1) Å · b = 5.7399(1) Å · c = 10.0875(2) Å
Cell angles: β = 113.899(1) °
Ratio a:b:c: 1 : 0.647 : 1.136
Unit cell volume: 469.97 Å³

Crystal structure

Chemical composition

Constituent elements: Mass composition breakdown
Element Atoms At. mass g/mol Mass g/mol Mass share
8OOxygen Oxygen 13 15.999 207.987
33.29%
57LaLanthanum Lanthanum 1 138.905 138.905
22.23%
25MnManganese Manganese 2 54.938 109.876
17.58%
14SiSilicon Silicon 3 28.085 84.255
13.48%
26FeIron Iron 1 55.845 55.845
8.94%
13AlAluminium Aluminium 1 26.982 26.982
4.32%
1HHydrogen Hydrogen 1 1.008 1.008
0.16%
Total 624.858 100.00%
Mass share = atoms × atomic mass ÷ molar mass × 100
From IMA formula

Mass composition breakdown
Element	Atoms	At. mass g/mol	Mass g/mol	Mass share
8OOxygen	Oxygen	13	15.999	207.987	33.29%
57LaLanthanum	Lanthanum	1	138.905	138.905	22.23%
25MnManganese	Manganese	2	54.938	109.876	17.58%
14SiSilicon	Silicon	3	28.085	84.255	13.48%
26FeIron	Iron	1	55.845	55.845	8.94%
13AlAluminium	Aluminium	1	26.982	26.982	4.32%
1HHydrogen	Hydrogen	1	1.008	1.008	0.16%
	Total	624.858	100.00%

Synonyms

Ferriandrosiet-(La)
IMA2013-127

In other languages

German: Ferriandrosit-(La) · IMA 2013-127
Italian: ferriandrosite-(La)
Japanese: ランタンフェリアンドロス石

Classification

Strunz

10th ed.

9.BG.05

9SilicatesClass
9.BSorosilicatesDivision
9.BGSorosilicates with mixed SiO₄ and Si₂O₇ groups; cations in octahedral [6] and greater coordinationGroup
9.BG.05Ferriandrosite-(La)Species

Group, growth & confusion

23 members

Literature, links & citation

Citations

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
2015Nagashima, Mariko, Nishio-Hamane, Daisuke, Tomita, Norimitsu, Minakawa, Tetsuo, Inaba, Sachio (2015) Ferriakasakaite-(La) and ferriandrosite-(La): new epidote-supergroup minerals from Ise, Mie Prefecture, Japan. Mineralogical Magazine, 79 (3) 735-753 doi:10.1180/minmag.2015.079.3.16DOI: 10.1180/minmag.2015.079.3.16
2016(2016) Ferriandrosite-(La). Handbook of Mineralogy. Mineralogical Society of America

Cite this entry

@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Ferriandrosite-(La) — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/ferriandrosite-la-45986},
  note      = {Accessed 2026-05-11}
}