Protoenstatite

Where it forms, where it's found

Type locality: Dust Devil Mine
Plush
Lake County
Oregon
USA
42.7132°, -119.8691°

1recorded occurrences

Source · OpenStreetMap

Crystallography

Crystal system: Orthorhombic
Space group: Pbcn
Cell parameters: a = 9.25(1) Å · b = 8.78(1) Å · c = 5.32(1) Å
Ratio a:b:c: 1 : 0.949 : 0.575

Crystal structure

Chemical composition

Constituent elements: Mass composition breakdown
Element Atoms At. mass g/mol Mass g/mol Mass share
8OOxygen Oxygen 6 15.999 95.994
47.81%
14SiSilicon Silicon 2 28.085 56.170
27.98%
12MgMagnesium Magnesium 2 24.305 48.610
24.21%
Total 200.774 100.00%
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	6	15.999	95.994	47.81%
14SiSilicon	Silicon	2	28.085	56.170	27.98%
12MgMagnesium	Magnesium	2	24.305	48.610	24.21%
	Total	200.774	100.00%

Synonyms

IMA2016-117
Protoenstatiet

In other languages

German: IMA 2016-117 · Protoenstatit

Classification

Strunz

10th ed.

9.DA

9SilicatesClass
9.DInosilicatesDivision
9.DAInosilicates with 2-periodic single chains, Si₂O₆; pyroxene familyGroup
9.DAProtoenstatiteSpecies

Group, growth & confusion

3 members

2 minerals

Literature, links & citation

Citations

2017(2017) Protoenstatite. Handbook of Mineralogy. Mineralogical Society of America
2017Hålenius, U., Hatert, F., Pasero, M., Mills, S. J. (2017) New minerals and nomenclature modifications approved in 2017, CNMNC Newsletter No 37. Mineralogical Magazine, 81 (3) 737-742 doi:10.1180/minmag.2017.081.039DOI: 10.1180/minmag.2017.081.039
2017Xu, Huifang, Hill, Tina R., Konishi, Hiromi, Farfan, Gabriela (2017) Protoenstatite: A new mineral in Oregon sunstones with “watermelon” colors. American Mineralogist, 102 (10) 2146-2149 doi:10.2138/am-2017-6186DOI: 10.2138/am-2017-6186

Cite this entry

@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Protoenstatite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/protoenstatite-51821},
  note      = {Accessed 2026-05-11}
}