Euchlorine

Euchlorine (KNaCu₃(SO₄)₃O) is a rare emerald-green sulfate mineral found naturally occurring as a sublimate in fumaroles around volcanic eruptions.^[3][4][5] It was first discovered in fumaroles of the 1868 eruption at Mount Vesuvius in Campania, Italy by Arcangelo Scacchi.^[2][9][10] The name 'euchlorine' comes from the Greek word εΰχλωρος meaning "pale green" in reference to the mineral's color, other reported spellings include euclorina, euchlorin, and euchlorite.^[2][9][10]

Euchlorine, Euclorina, Euchlorin, Euchlorite
General
Category	Sulfate mineral
Formula (repeating unit)	KNaCu3(SO4)3O
IMA symbol	Ecr[1]
Strunz classification	7.BC.30
Dana classification	30.3.1.1
Crystal system	Monoclinic
Space group	C2/c
Unit cell	a = 18.41(5) Å, b = 9.43(3) Å, c = 14.21(5) Å, β = 113.7(3)°; Z = 8
Identification
Color	Emerald-green, dark green
Crystal habit	Single crystals, tabular, incrustation
Streak	Pistachio green
Density	3.28 (measured), 3.28 (calculated)
Optical properties	Biaxial (+), moderate relief, emerald green color (transmitted light)
Refractive index	nα = 1.580, nβ = 1.605, nγ = 1.644
Birefringence	δ = 0.064
Pleochroism	X: Pale grass-green, Y: Grass-green, Z: Bright yellow-green
2V angle	Moderately large (measured)
Dispersion	r < v
Solubility	Partially soluble in water
References	[2][3][4][5][6][7][8]

The ideal formula of euchlorine is KNaCu₃(SO₄)₃O though calcium (Ca) and magnesium (Mg) occasionally substitute into the crystal lattice.^[11] Euchlorine is structurally related to puninite (Na₂Cu₃(SO₄)₃O) and fedotovite (K₂Cu₃(SO₄)₃O), all of which are included in the euchlorine group of minerals.^[4][12]

One of the distinguishing physical properties helpful for identifying euchlorine in hand sample is its streak, which is a pistachio-green color.^[5][10] If trying to find euchlorine in the field, wear protective clothing as the volcanic fumaroles around which it occurs can be very hot (approximately 300 to 650 °C, 580 to 1200 °F) and can cause severe steam burns if not adequately protected.^[13][14]

Geologic occurrence

Mount Vesuvius, Naples, Italy is the type locality of euchlorine.^{[2][3][4][5][10]} It occurred as a sublimate in fumaroles (hot vents of steam and other volcanic gases) that formed during the 1868 volcanic eruption, it has also been found in fumaroles during eruptions at the same location in 1892 and 1893.^[2][13] Mineral associations at this site include dolerophanite, eriochalcite, chalcocyanite, melanothallite, anglesite, atacamite, cryptochalcite, palmierite, barite, and natrochalcite.^[3][13]

Euchlorine has also been found at Izalco Volcano in El Salvador.^[3][4] In 1987 euchlorine was one of the minerals found in association with Mcbirneyite when it was first discovered in fumaroles at the summit of Izalco Volcano.^[15] Other mineral associations at this location include stoiberite, fingerite, ziesite, and thenardite.^[15]

In Russia, euchlorine has been found in association with multiple new minerals discovered in the 2000s and 2010s.^{[16][17][18][19][20][21]}

At fumarole deposits in the North Breach from the Tolbachik Volcano eruption of the Great Fissure on the Kamchatka Peninsula euchlorine (as euchlorite) was found associated with newly discovered mineral avdoninite and reported around 2005–2007.^[16] In 2012 the discovery of a new fumarolic mineral cupromolybdite found in the New Tolbachik Scoria Cones in association with euchlorine at Tolbachik Volcano was published.^[17] Not long after, in early 2013, yaroshevskite was reported newly discovered from scoria cones of the Great Fissure Eruption at Tolbachik Volcano in association with euchlorine.^[18] Two new minerals were reported discovered in 2014 from two different fumaroles at Tolbachik Volcano in association with euchlorine.^[19] The first mineral was wulffite and the second was parawulffite, both from the area of the Northern Breakthrough during the Great Fissure Eruption.^[19] Work conducted on fumarole deposits from the same eruption found euchlorine being associated with a newly discovered mineral called itelmenite and was reported in 2015 and published in mid to late 2018.^[20][21]

In addition to the minerals discovered, euchlorine was found associated with minerals including:

• Avdoninite – Paratacamite, atacamite, belloite, and langbeinite (Yadovitaya Fumarole, Second Cinder Cone, North Breach, Great Fissure Tolbachik Eruption, Tolbachik Volcano, Kamchatka, Russia^[16])
• Cupromolybdite – Piypite, fedotovite, vergasovaite, hematite, magnetite, aphthitalite, langbeinite, palmierite, As-bearing orthoclase, lammerite, klyuchevskite, alumoklyuchevskite, lyonsite, pseudolyonsite, averievite, rutile, and native gold (New Tolbachik Scoria Cones, Tolbachik Volcano, Kamkatchka, Russia^[17])
• Yaroshevskite – Fedotovite, hematite, tenorite, lyonsite, melanothallite, atlasovite, kamchatkite, secondary avdoninite, belloite, chalcanthite (Yadovitaya fumarole, Second Scoria Cone, Northern Breakthrough, Great Tolbachik Fissure Eruption, Tolbachik Volcano, Kamkatchka, Russia^[18])
• Wulffite – Aphthitalite, tenorite, hematite, lammerite, johillerite, fluoborite (Arsenatnaya Fumarole, Second Scoria Cone, Northern Breakthrough, Great Tolbachik Fissure Eruption, Tolbachik Volcano, Kamkatchka, Russia^[19])
• Parawulffite – Fedotovite, hematite, langbeinite, steklite (Yadovitaya Fumarole, Second Scoria Cone, Northern Breakthrough, Great Tolbachik Fissure Eruption, Tolbachik Volcano, Kamkatchka, Russia^[19])
• Itelmenite – Anhydrite, saranchinaite, hermannjahnite, thenardite (as thénardite), aphthitalite, and hematite (Naboko Scoria Cone, Tolbachik Volcano Fissure Eruption, Tolbachik Volcano, Kamkatchka, Russia^[21])

Marcel Mine in Radlin, Poland has also discovered what may be euchlorine in the 2010s.^[22]

See also

• List of minerals recognized by the International Mineralogical Association (E)
• List of minerals

References

1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
2. Palache, C.; Berman, H.; Frondel, C. (1951). "The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837–1892, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc." John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged: pp. 571(as Euchlorin with other spellings listed including Euchlorine, Euchlorinite, Euclorina).
3. Handbook of Mineralogy – Euchlorine Archived 3 March 2016 at the Wayback Machine.
4. Mindat.org – Euchlorine.
5. Webmineral – Euchlorine.
6. Scordari, F. and Stasi, F. (1990). "The crystal structure of euchlorine, NaKCu₃O(SO₄)₃" Neues Jahrbuch für Mineralogie, Abhandlungen, 161: 241–253.
7. Jambor, J.L.; Grew, E.S. (1991). "New mineral names". American Mineralogist, 76(1–2): 299–305.
8. Eugenio Scacchi: Sull’ euclorina, sull’ eriocaleo e sul melanotallo. In: Rendiconto dell'Accademia delle Scienze Fisiche e Matematiche. 23:158–165.
9. A. Scacchi (1869) (as Euclorina).
10. EUROmin Project – Euchlorine.
11. Jambor, J.L.; Puziewicz, J. (1990). "New mineral names". American Mineralogist, 75(9–10): 1209–1216.
12. Siidra, O.I.; Nazarchuk, E.V.; Zaitsev, A.N.; Lukina, E.A.; Avdontseva, E.Y.; Vergasova, L.P.; Vlasenko, N.S.; Filatov, S.K.; Turner, R.; Karpov, G.A. (2017). "Copper oxosulphates from fumaroles of Tolbachik volcano: puninite, Na2Cu3O(SO4)3 –a new mineral species and structure refinements of kamchatkite and alumoklyuchevskite". European Journal of Mineralogy, 29(3): 499–510.
13. Balassone, G.; Petti, C.; Mondillo, N.; Panikorovskii, T.L.; de Gennaro, R.; Cappelletti, P.; Altomare, A.; Corriero, N.; Cangiano, M.; D'Orazio, L. (2019). "Copper Minerals at Vesuvius Volcano (Southern Italy): A Mineralogical Review". Minerals, 9(12): 730.
14. Fox News (September 12, 2017). "Italian parents killed in volcanic field trying to rescue their son".
15. Hughes, J.M.; Christian, B.S.; Finger, L.W.; Malinconico, L.L. (1987). "Mcbirneyite, Cu₃(VO₄)₂, a new sublimate mineral from the fumaroles of Izalco volcano, El Salvador". Journal of Volcanology and Geothermal Research, 33(1–3): 183–190.
16. Chukanov, N.V.; Murashko, M.N.; Zadov, A.E.; Bushmakin, A.F. (2007). "Avdoninite, K₂Cu₅Cl₈(OH)₄ · H₂O, a New Mineral Species from Volcanic Exhalations and the Technogenic Zone at Volcanic-Hosted Massive Sulfide Deposits". Geology of Ore Deposits, 49(7): 505–508.
17. Zelenski, M.E.; Zubkova, N.V.; Pekov, I.V.; Polekhovsky, Y.S.; Pushcharovsky, D.Y. (2012). "Cupromolybdite, Cu3O(MoO4)2, a new fumarolic mineral from the Tolbachik volcano, Kamchatka Peninsula, Russia". European Journal of Mineralogy, 24(4): 749–757.
18. Pekov, I.V.; Zubkova, N.V.; Zelenski, M.E.; Yapaskurt, V.O.; Polekhovsky, Y.S.; Fadeeva, O.A.; Pushcharovsky, D.Y. (2013). "Yaroshevskite, Cu₉O₂(VO₄)₄Cl₂, a new mineral from the Tolbachik volcano, Kamchatka, Russia". Mineralogical Magazine, 77(1): 107–116.
19. Pekov, I.V.; Zubkova, N.V.; Yapaskurt, V.O.; Belakovskiy, D.I.; Chukanov, N.V.; Lykova, I.S.; Savelyev, D.P.; Sidorov, E.G.; Pushcharovsky, D.Y. (2014). "WULFFITE, K3NaCu4O2(SO4)4, AND PARAWULFFITE, K5Na3Cu8O4(SO4)8, TWO NEW MINERALS FROM FUMAROLE SUBLIMATES OF THE TOLBACHIK VOLCANO, KAMCHATKA, RUSSIA". The Canadian Mineralogist, 52(4): 699–716.
20. Nazarchuk, E.V.; Siidra, O.I.; Agakhanov, A.A.; Lukina, E.A.; Avdontseva, E.Y.; Vergasova, L.P.; Filatov, S.K.; Karpov, G.A. (2015). "Itelmenite, IMA2015-047", CNMNC Newsletter No. 27, October 2015, page 1225; Mineralogical Magazine, 79, 1229–1236.
21. Nazarchuk, E.V.; Siidra, O.I.; Agakhanov, A.A.; Lukina, E.A.; Avdontseva, E.Y.; Karpov, G.A. (2018). "Itelmenite, Na₂CuMg₂(SO₄)₄, a new anhydrous sulfate mineral from the Tolbachik volcano". Mineralogical Magazine, 82(6): 1233–1241.
22. Mindat.org – Marcel Mine.

Bibliography

• Palache, P.; Berman H.; Frondel, C. (1960). "Dana's System of Mineralogy, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. (Seventh Edition)" John Wiley and Sons, Inc., New York, pp. 571.