Ecdemite
A valid IMA mineral species - grandfathered
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About Ecdemite
Formula:
Pb6Cl4(As2O7)
the study of Perchiazzi et al. (2019) shows ecdemite to be based on litharge-like defective layers. The layers formula is {Pb2[Pb4O](AsO3)2}4+.
Colour:
Greenish-yellow, yellow
Lustre:
Vitreous, Greasy
Hardness:
2½ - 3
Specific Gravity:
7.14
Crystal System:
Monoclinic
Name:
From the Greek ÎÎșÎŽÎ·ÎŒÎżÏ for "unusual" or "outstanding", in allusion to the composition.
A representative of layered lead oxyhalides group.
Unique Identifiers
Mindat ID:
1363
Long-form identifier:
mindat:1:1:1363:1
GUID
(UUID V4):
(UUID V4):
b27b40f9-da76-4dab-bcbf-811e7e284744
IMA Classification of Ecdemite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Pb6As2O7Cl4
Classification of Ecdemite
3.DC.65
3 : HALIDES
D : Oxyhalides, hydroxyhalides and related double halides
C : With Pb (As,Sb,Bi), without Cu
3 : HALIDES
D : Oxyhalides, hydroxyhalides and related double halides
C : With Pb (As,Sb,Bi), without Cu
46.2.1.1
46 : ANTIMONITES AND ARSENITES CONTAINING HYDROXYL OR HALOGEN
2 : Miscellaneous
46 : ANTIMONITES AND ARSENITES CONTAINING HYDROXYL OR HALOGEN
2 : Miscellaneous
23.7
23 : Arsenites
23 : Arsenites
Mineral Symbols
As of 2021 there are now IMAâCNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Symbol | Source | Reference |
---|---|---|
Ecd | IMAâCNMNC | Warr, L.N. (2021). IMAâCNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Ecdemite
Vitreous, Greasy
Transparency:
Translucent
Comment:
Lustre vitreous on cleavages and greasy on fractures
Colour:
Greenish-yellow, yellow
Streak:
Light yellow
Hardness:
2½ - 3 on Mohs scale
Cleavage:
Distinct/Good
On {001}, distinct.
On {001}, distinct.
Density:
7.14 g/cm3 (Measured) 7.3 g/cm3 (Calculated)
Optical Data of Ecdemite
Type:
Uniaxial (-)
RI values:
nω = 2.320 nε = 2.250
Max Birefringence:
δ = 0.070
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:
Very High
Chemistry of Ecdemite
Mindat Formula:
Pb6Cl4(As2O7)
the study of Perchiazzi et al. (2019) shows ecdemite to be based on litharge-like defective layers. The layers formula is {Pb2[Pb4O](AsO3)2}4+.
the study of Perchiazzi et al. (2019) shows ecdemite to be based on litharge-like defective layers. The layers formula is {Pb2[Pb4O](AsO3)2}4+.
Elements listed:
Crystallography of Ecdemite
Crystal System:
Monoclinic
Class (H-M):
2 - Sphenoidal
Space Group:
P21
Setting:
P21
Cell Parameters:
a = 10.82(4) Å, b = 10.826(2) Å, c = 6.97(1) Å
β = 113.26(2)°
β = 113.26(2)°
Ratio:
a:b:c = 0.999 : 1 : 0.644
Unit Cell V:
750.09 Ă
Âł (Calculated from Unit Cell)
Morphology:
Crystals small tabular and in foliated masses.
Comment:
from structure refinement by Perchiazzi et al. (2019), Harstigen material; previously thought to be tetragonal.
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
2.85 Ă | (100) |
3.66 Ă | (80) |
2.72 Ă | (80) |
2.07 Ă | (70) |
1.591 Ă | (70) |
1.92 Ă | (60) |
1.652 Ă | (50) |
Comments:
LĂ„ngban mine, Sweden.
Type Occurrence of Ecdemite
Co-Type Localities:
Geological Setting of Type Material:
Metamorphosed Fe-Mn ore body.
Associated Minerals at Type Locality:
Synonyms of Ecdemite
Other Language Names for Ecdemite
Common Associates
Associated Minerals Based on Photo Data:
10 photos of Ecdemite associated with Paralaurionite | PbCl(OH) |
9 photos of Ecdemite associated with Rhodonite | CaMn3Mn[Si5O15] |
8 photos of Ecdemite associated with Phosgenite | Pb2CO3Cl2 |
5 photos of Ecdemite associated with Wulfenite | Pb(MoO4) |
5 photos of Ecdemite associated with Fluorite | CaF2 |
4 photos of Ecdemite associated with Calcite | CaCO3 |
4 photos of Ecdemite associated with Laurionite | PbCl(OH) |
3 photos of Ecdemite associated with Cerussite | PbCO3 |
3 photos of Ecdemite associated with Aragonite | CaCO3 |
2 photos of Ecdemite associated with Anglesite | PbSO4 |
Related Minerals - Strunz-mindat Grouping
3.DC. | Lucabindiite | (K,NH4)As4O6(Cl,Br) |
3.DC. | Torrecillasite | Na(As,Sb)3+4O6Cl |
3.DC. | Gajardoite | KCa0.5As3+4O6Cl2 · 5H2O |
3.DC. | Cuatrocapaite-(NHâ) | (NH4)3(NaMgâ»)(As2O3)6Cl6 · 16H2O |
3.DC. | Cuatrocapaite-(K) | K3(NaMgâ»)(As2O3)6Cl6 · 16H2O |
3.DC. | Napoliite | Pb2OFCl |
3.DC.05 | Laurionite | PbCl(OH) |
3.DC.05 | Paralaurionite | PbCl(OH) |
3.DC.05 | Russoite | (NH4)ClAs2O3(H2O)0.5 |
3.DC.05 | Mauriziodiniite | (NH4)(As2O3)2I |
3.DC.10 | Fiedlerite | Pb3FCl4(OH) · H2O |
3.DC.15 | Penfieldite | Pb2Cl3(OH) |
3.DC.15 | Telluroperite | Pb3TeO4Cl2 |
3.DC.20 | Laurelite | Pb7F12Cl2 |
3.DC.25 | Bismoclite | BiOCl |
3.DC.25 | Matlockite | PbFCl |
3.DC.25 | Rorisite | CaFCl |
3.DC.25 | Zavaritskite | (BiO)F |
3.DC.25 | Zhangpeishanite | BaFCl |
3.DC.30 | Nadorite | PbSbClO2 |
3.DC.30 | Perite | PbBiClO2 |
3.DC.40 | Thorikosite | Pb3Cl2(OH)(SbO3,AsO3) |
3.DC.45 | Mereheadite | Pb47Cl25(OH)13O24(CO3)(BO3)2 |
3.DC.50 | Blixite | Pb8O5(OH)2Cl4 |
3.DC.52 | Rumseyite | Pb2OClF |
3.DC.55 | Pinalite | Pb3WO5Cl2 |
3.DC.55 | Vladkrivovichevite | [Pb32O18][Pb4Mn2O]Cl14(BO3)8 · 2H2O |
3.DC.57 | Yeomanite | Pb2O(OH)Cl |
3.DC.60 | Lorettoite | Pb7O6Cl2 |
3.DC.60 | Symesite | Pb10(SO4)O7Cl4 · H2O |
3.DC.62 | Sarawakite (of Frenzel) | Sb, O, Cl (?) |
3.DC.70 | Mendipite | Pb3Cl2O2 |
3.DC.75 | Damaraite | Pb3Cl(OH)O2 |
3.DC.80 | Onoratoite | Sb8Cl2O11 |
3.DC.95 | Barstowite | Pb4Cl6(CO3) · H2O |
Other Information
Notes:
Soluble in HNO3 or warm HCl, and in alkalies.
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 Ecdemite
mindat.org URL:
https://www.mindat.org/min-1363.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Ecdemite
Reference List:
Larsen, Esper S. (1921) The microscopic determination of the nonopaque minerals. Bulletin Vol. 679. US Geological Survey doi:10.3133/b679 p.71
Perchiazzi, Natale, HĂ„lenius, Ulf, Vignola, Pietro, Demitri, Nicola (2019) Crystal-chemical study of ecdemite from Harstigen, a new natural member of the layered lead oxyhalides group. European Journal of Mineralogy, 31 (3) 609-617 doi:10.1127/ejm/2019/0031-2853
Localities for Ecdemite
Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
â - 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).
Struck out - Mineral was erroneously reported from this locality.
Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
All localities listed without proper references should be considered as questionable.
China | |
| Li et al. (1985) |
Greece | |
| Schnorrer-Köhler et al. (1981) |
Gelaude et al. (1996) | |
Gelaude et al. (1996) | |
www.mineralienatlas.de (2014) | |
Gelaude et al. (1996) | |
Gelaude et al. (1996) | |
Gelaude et al. (1996) | |
Gelaude et al. (1996) | |
Italy | |
| www.comune.pisa.it (2000) |
| Muenchener Micromounter-Lithothek |
Spain | |
| Van der Berg et al. (2020) |
Sweden (TL) | |
| Geologiska Föreningens I Stockholm. Förhandlinger (1877) +2 other references |
| Sillén et al. (1941) +2 other references |
| Flink (1888) +2 other references |
USA | |
| Van Nostrand Reinholt Press: 325. +2 other references |
| Winchell (1914) |
Winchell (1914) | |
| Castor et al. (2004) |
Quick NavTopAbout EcdemiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Harstigen Mine, Pajsberg, Persberg ore district, Filipstad, VĂ€rmland County, Sweden