Alacránite
A valid IMA mineral species
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About Alacránite
Formula:
As8S9
Colour:
Orange to pale gray with rose-yellow internal reflections
Lustre:
Vitreous, Resinous, Greasy
Hardness:
1½
Specific Gravity:
3.43
Crystal System:
Monoclinic
Name:
Named after its discovery locality in Chile.
Different from (unnamed) natural beta-As4S4.
Unique Identifiers
IMA Classification of Alacránite
Approved
Approval year:
1985
First published:
1986
Classification of Alacránite
2.FA.20
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
F : Sulfides of arsenic, alkalies; sulfides with halide, oxide, hydroxide, H2O
A : With As, (Sb), S
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
F : Sulfides of arsenic, alkalies; sulfides with halide, oxide, hydroxide, H2O
A : With As, (Sb), S
2.8.22.
2 : SULFIDES
8 : AmXp, with m:p = 1:1
2 : SULFIDES
8 : AmXp, with m:p = 1:1
3.7.6
3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
7 : Sulphides etc. of V, As, Sb and Bi
3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
7 : Sulphides etc. of V, As, Sb and Bi
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference |
|---|---|---|
| Acr | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Alacránite
Vitreous, Resinous, Greasy
Transparency:
Translucent
Colour:
Orange to pale gray with rose-yellow internal reflections
Comment:
yellow-orange in transmitted light
Streak:
Yellow-orange
Hardness:
1½ on Mohs scale
Hardness:
VHN20=69 kg/mm2 - Vickers
Tenacity:
Very brittle
Cleavage:
Imperfect/Fair
imperfect on {100}
imperfect on {100}
Fracture:
Conchoidal
Density:
3.43(3) g/cm3 (Measured) 3.43 g/cm3 (Calculated)
Optical Data of Alacránite
Type:
Biaxial (+)
RI values:
nα = 2.390(1) nγ = 2.520(2)
Max Birefringence:
δ = 0.130
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
r < v
Reflectivity:
| Wavelength | R1 | R2 |
|---|---|---|
| 400nm | 13.0% | 14.0% |
| 425nm | 13.2% | 14.6% |
| 450nm | 13.3% | 14.8% |
| 475nm | 13.4% | 14.8% |
| 500nm | 13.3% | 14.5% |
| 525nm | 13.1% | 14.3% |
| 550nm | 13.2% | 14.5% |
| 575nm | 13.4% | 14.7% |
| 600nm | 13.5% | 14.8% |
| 625nm | 13.6% | 14.9% |
| 650nm | 13.7% | 15.0% |
| 675nm | 13.8% | 15.0% |
| 700nm | 13.9% | 15.1% |
Graph shows reflectance levels at different wavelengths (in nm). Top of box is 100%. Peak reflectance is 15.1%.
R1 shown in black, R2 shown in red
Colour in reflected light:
Light gray
Internal Reflections:
Rose-yellow
Chemistry of Alacránite
Mindat Formula:
As8S9
Elements listed:
Crystallography of Alacránite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P2/b
Setting:
P2/c
Cell Parameters:
a = 9.942 Å, b = 9.601 Å, c = 9.178 Å
β = 101.94°
β = 101.94°
Ratio:
a:b:c = 1.036 : 1 : 0.956
Unit Cell V:
857.1 ų
Z:
2
Morphology:
Crystals are pinacoidal, prismatic, and flattened on [100] , striated parallel [001] on {100} , other faces dull or tarnished, to 1 mm; as subhedral flattened and prismatic grains.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.89 Å | (40) |
| 5.91 Å | (90) |
| 5.11 Å | (80) |
| 4.05 Å | (70) |
| 3.291 Å | (50) |
| 3.064 Å | (100) |
| 2.950 Å | (90) |
Comments:
Uzon caldera, Kamchatka, Russia (ICDD 42-537).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 11 : Volcanic fumarole minerals; reduced phases (see also #45) | |
| Stage 3b: Earth’s earliest hydrosphere | >4.45 |
| 12 : Hadean hydrothermal subsurface sulfide deposits (see also #33) | |
| High-𝑇 alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Geological Setting:
in the condensation zone of a hydrothermal Hg–Sb–As system as cement in a sandy gravel (Uzon caldera, Russia); formed
at low temperatures in a polymetallic hydrothermal deposit on a submarine seamount (Conical Seamount, Papua New Guinea).
at low temperatures in a polymetallic hydrothermal deposit on a submarine seamount (Conical Seamount, Papua New Guinea).
Type Occurrence of Alacránite
Co-Type Localities:
Place of Conservation of Type Material:
Il’menskii Preserve Museum, Miass; A.E. Fersman Mineralogical Museum, Academy of Sciences, Moscow, Russia.
Geological Setting of Type Material:
In hydrothermal As–S veins
Associated Minerals at Type Locality:
Reference:
Popova, V.I., Popov, V.A., Clark, A., Polyakov, V.O., Borisovskii, S.E. (1986) Alacránite, As8S9–a new mineral. Zapiski Vsesoyuznogo Mineralogicheskogo Obshchestva: 115(3): 360-368.
Synonyms of Alacránite
Other Language Names for Alacránite
Relationship of Alacránite to other Species
Forms a series with:
Common Associates
Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 2.FA. | Anorpiment | As2S3 |
| 2.FA. | Bonazziite | As4S4 |
| 2.FA. | Paradimorphite | As4S3 |
| 2.FA.05 | Duranusite | As4S |
| 2.FA.10 | Dimorphite | As4S3 |
| 2.FA.15b | Pararealgar | As4S4 |
| 2.FA.15a | Realgar | As4S4 |
| 2.FA.15d | UM1970-18-S:As | As4S4 |
| 2.FA.25 | Uzonite | As4S5 |
| 2.FA.30 | Laphamite | As2Se3 |
| 2.FA.30 | Orpiment | As2S3 |
| 2.FA.35 | Getchellite | AsSbS3 |
| 2.FA.40 | Wakabayashilite | [(As,Sb)6S9][As4S5] |
| 2.FA.40 | Kalgoorlieite | As2Te3 |
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Alacránite
mindat.org URL:
https://www.mindat.org/min-91.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
References for Alacránite
Reference List:
Clark, Alan H. (1970) Alpha-arsenic sulfide, from Mina Alacrán, Pampa Larga, Chile. American Mineralogist, 55 (7-8) 1338-1344 [as unnamed "AsS" modification]
Hawthorne, Frank C., Burke, Ernst A. J., Ercit, T. Scott, Grew, Edward S., Grice, Joel D., Jambor, John L., Puziewicz, Jacek, Roberts, Andrew C., Vanko, David A. (1988) New Mineral Names. American Mineralogist, 73 (1-2) 189-199
Burns, P. C., Percival, J. B. (2001) Alacranite, As4S4: a new occurrence, new formula, and determination of the crystal structure. The Canadian Mineralogist, 39 (3) 809-818 doi:10.2113/gscanmin.39.3.809
Bonazzi, Paola, Bindi, Luca, Popova, Valentina, Pratesi, Giovanni, Menchetti, Silvio (2003) Alacranite, As8S9: structural study of the holotype and re-assignment of the original chemical formula. American Mineralogist, 88 (11) 1796-1800 doi:10.2138/am-2003-11-1220
Localities for Alacránite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Bulgaria | |
| Miadenova (2000) |
Chile (TL) | |
| Clark (1970) +4 other references |
Czech Republic | |
| Pauliš P. Mineralogické lokality ... |
| Žáček et al. (1998) |
| Scharm B. |
Germany | |
| Walenta (1992) |
| |
| |
| Walenta (1992) |
| Wittern (2001) |
| Thalheim +1 other reference |
| |
| T. Witzke & F. Rüger: Lapis 1998 (7/8) |
Italy | |
| Russo et al. (2017) |
Japan | |
| The Mineral Species of Japan (5th ed) +1 other reference |
Kyrgyzstan | |
| Bindi et al. (2015) |
New Zealand | |
| Kerr et al. (2018) |
| Kerr et al. (2018) | |
Papua New Guinea | |
| Rod Martin Collection |
| Burns et al. (2001) +2 other references |
Romania | |
| Szakáll et al. (2006) +2 other references |
Russia (TL) | |
| Popova et al. (1986) +2 other references |
| Pekov (1998) | |
| Bortnikova et al. (2017) |
Tajikistan | |
| Karpenko et al. (2023) |
Quick NavTopAbout AlacrániteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Uzon Caldera, Kronotsky Reserve, Yelizovsky District, Kamchatka Krai, Russia