Chemistry:Tsugaruite
| Tsugaruite | |
|---|---|
 Pb28As15S50Cl | |
| General | |
| Category | Sulfosalt mineral |
| Formula (repeating unit) | Pb28As15S50Cl |
| Strunz classification | 2.JB.30 |
| Crystal system | Orthorhombic |
| Space group | Pnn2 (space group 34) |
| Unit cell | a = 8.0774(10) Å, b = 15.1772(16) Å, c = 38.129(4) Å; Z = 16 |
| Identification | |
| Color | Lead-grey |
| Crystal habit | Tabular |
| Cleavage | None observed |
| Fracture | Irregular/uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 2.5 to 3 |
| |re|er}} | Metallic |
| Streak | Lead-grey |
| Diaphaneity | Opaque |
| Specific gravity | 6.83 (Calculated) |
| Density | 6.83 g/cm3 (Calculated) |
| Optical properties | Weakly bireflectant |
| Pleochroism | Weakly pleochroic |
| References | [1] |
Tsugaruite is a sulfosalt mineral with the chemical formula Pb
28As
15S
50Cl. It was first discovered in 1997 in a thin baryte veinlet at the Yunosawa mine in Ikarigaseki, Aomori. In 1998, the International Mineralogical Association approved it as a new mineral species.[2][3] The mineral was named for its type locality's location in Japan's Tsugaru Peninsula.
When tsugaruite was originally discovered, its structure was uncertain and its chemical formula was believed to be Pb
4As
2S
7.[2] Tsugaruite has a hardness of 2.5-3 on the Mohs scale and is described as "opaque with a metallic lustre and lead-grey streak".[2] It is associated with jordanite and galena. The chemical similarity of tsugaruite to jordanite has caused confusion, resulting in earlier findings of tsugaruite being classified as jordanite.[2][4] It is orthorhombic and occurs as radiating groups of tabular crystals.[2][5] The structure is highly complex which is indicated by its large unit cell of 4674.3(9) Å3.[3][6] It is in space group Pnn2.[3] Tsugaruite is recognized as the first lead-arsenic chloro-sulfosalt.[3] Compared to jordanite, tsugaruite is slightly softer and darker, slightly greener, less pleochroic, and less anisotropic.[2] Chlorine occupies a specific position in its structure. This was discovered using electron probe microanalysis. The atomic ratio of tsugaruite is close to that of other lead-antimony chloro-sulfosalts and just above the atomic ratio of dadsonite.[3] Tsugaruite is found with jordanite but formed later. Due to its rarity, tsugarite is mostly studied for its mineralogical properties. Practical uses are still being researched,[2] primarily with X-ray crystallography.[3]
See also
References
- ↑ "Tsugaruite". https://www.mindat.org/min-7344.html.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 "Tsugaruite, Pb4As2S7, a new mineral species from the Yunosawa mine, Aomori Prefecture, Japan". Mineralogical Magazine Via Cambridge University Press 62 (6): 793–799. December 1998. doi:10.1180/002646198548179. Bibcode: 1998MinM...62..793S. https://rruff.geo.arizona.edu/doclib/MinMag/Volume_62/62-6-793.pdf. Retrieved October 16, 2025.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 "Determination of the Crystal Structure and Redefinition of Tsugaruite, Pb28As15S50Cl, the First Lead-Arsenic Chloro-Sulfosalt". The Canadian Mineralogist 59 (1): 125–137. 2021. doi:10.3749/canmin.2000005. Bibcode: 2021CaMin..59..125B.
- ↑ "Jordanite". RRUFF Project. University of Arizona. https://rruff.geo.arizona.edu/doclib/hom/jordanite.pdf.
- ↑ Quaternary Alloys Based on IV-VI and IV-VI2 Semiconductors. Boca Raton, Florida: CRC Press. 2023. doi:10.1201/9781003123484. ISBN 978-1-003-12348-4.
- ↑ "Sulfosalt systematics: a review. Report of the sulfosalt sub-committee of the IMA Commission on Ore Mineralogy". European Journal of Mineralogy 20 (1): 7–62. 2008. doi:10.1127/0935-1221/2008/0020-1778. Bibcode: 2008EJMin..20....7M. https://www.researchgate.net/publication/228355520. Retrieved October 19, 2025.
Further reading
- "Contribution to the crystal chemistry of lead-antimony sulfosalts: systematic Pb-versus-Sb crossed substitution in the plagionite homologous series, Pb2N−1(Pb1−xSbx)2(Sb1−xPbx)2Sb6S13+2N". European Journal of Mineralogy 32: 623–635. 2020. doi:10.5194/ejm-32-623-2020. https://ejm.copernicus.org/articles/32/623/2020/ejm-32-623-2020.pdf. Retrieved October 17, 2025.
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