Mindat Logo
Home Page Log In Messageboard The Mindat Directory
Register Search Pages Mineral Chatroom The Mindat Store

Acanthite

This page is currently not sponsored. Click here to sponsor this page.
Big Photo

Himmelsfürst Mine, Brand-Erbisdorf, Freiberg District, Erzgebirge, Saxony, Germany
© Stephan Wolfsried

Show Acanthite Photos (628)



Formula:
Ag
 
2
S
System:MonoclinicColour:lead grey, black
Lustre:MetallicHardness:2 - 2½
Name:from the Greek άκανθα ("akantha") meaning "thorn", in allusion to its crystal shape.
Isostructural with:Aguilarite


Acanthite is the low-temperature modification of silver sulphide.
All natural silver sulphide specimens at room temperature are acanthite.
The structure of Argentite, the high-temperature cubic (isometric) form cannot be quenched. At atmospheric pressure, pure argentite is stable above 177°C and acanthite is stable below 177°C. The tarnish on sterling silver is chemically the same as acanthite.

Classification of Acanthite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:2/B.05-10
Strunz 9th edition ID:2.BA.35
Nickel-Strunz 10th (pending) edition ID:2.BA.35

2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
B : Metal Sulfides, M: S > 1: 1 (mainly 2: 1)
A : With Cu, Ag, Au
Dana 7th edition ID:2.4.1.1
Dana 8th edition ID:2.4.1.1

2 : SULFIDES
4 : AmBnXp, with (m+n):p = 2:1
Hey's CIM Ref.:3.2.1

3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
2 : Sulphides etc. of Ag
mindat.org URL:http://www.mindat.org/min-10.html
Please feel free to link to this page.

Type Occurrence of Acanthite

Type Locality:Jáchymov (St Joachimsthal), Jáchymov (St Joachimsthal) District, Krušné Hory Mts (Erzgebirge), Karlovy Vary Region, Bohemia (Böhmen; Boehmen), Czech Republic
Year of Discovery:1855

Occurrences of Acanthite

Geological Setting:A common silver species in moderately low-temperature hydrothermal sulphide veins, and in zones of secondary enrichment.

Widespread in silver deposits. Localities for fine primary and paramorphic crystals include: Jáchymov (St Joachimsthal), Czech Republic [TL]; In Germany, at Freiberg, Schneeberg, Annaberg, and Marienberg, Saxony; and from St Andreasberg, Harz. In Mexico, large paramorphs from Arizpe, Sonora; In the Rayas and other mines at Guanajuato; And from many mines in Zacatecas, Chihuahua, etc; In the USA, at Butte, Silver Bow Co., Montana; Tonopah, Nye Co. and the Comstock Lode, Virginia City, Storey Co., Nevada; From various mines at Cobalt, Ontario, Canada; At Chañarcillo, south of Copiapó, Atacama, Chile.

Physical Properties of Acanthite

Lustre:Metallic
Diaphaneity (Transparency):Opaque
Colour:lead grey, black
Streak:lead grey
Hardness (Mohs):2 - 2½
Hardness (Vickers):VHN50=21 - 25 kg/mm2
Hardness Data:Measured
Tenacity:Sectile
Cleavage:None Observed
Fracture:Sub-Conchoidal
Density (measured):7.2 - 7.4 g/cm3
Density (calculated):7.24 g/cm3

Crystallography of Acanthite

Crystal System:Monoclinic
Class (H-M):2/m - Prismatic
Space Group:P21/m {P1 1 21/m} {P21/m} {P1 21/m 1}
Cell Parameters:a = 4.229Å, b = 6.931Å, c = 7.862Å
β = 99.61°
Ratio:a:b:c = 0.61 : 1 : 1.134
Unit Cell Volume:V 227.21 ų (Calculated from Unit Cell)
Z:4
Morphology:Typically found as pseudo-cubic and pseudo-octahedral crystals, paramorphic after argentite. Also found as thorn-shaped monoclinic crystals, usually small to microscopic in size. Primary crystals are rare, prismatic to long prismatic, elongated along [001], to 2.5 cm, may be tubular; massive.
Crystal Atlas:
Image Loading
Click on an icon to view
Argentite no.11 - Goldschmidt (1913-1926)
Argentite - {100}, modified

About Crystal Atlas

You may need to scroll this box using your mouse to view the full instructions.

The mindat.org Crystal Atlas allows you to view a selection of crystal drawings of real and idealised crystal forms for this mineral and, in certain cases, 3d rotating crystal objects. You need Java to see these. You can download Java for free - click here to download Java

The 3d models and java code are kindly provided by www.smorf.nl. You can control the movement of the models by holding down the left mouse-button over the 3d model and moving your mouse. Keyboard controls are:

: default positions
t/T: decrease/increase transparency x/X: next/previous texture
b/B: next/previous background w: toggle wireframe
s: toggle sticks m: toggle miller indices
k: toggle crystallographic axes =/-: zoom in/out
r: stop/start rotation 1/2/3
X-Ray Powder Diffraction:
d-spacingIntensity
3.08(60)
2.84(70)
2.61(100)
2.58(70)
2.46(70)
2.44(80)
2.42(60)
2.38(80)

Optical Data of Acanthite

Type:Anisotropic
Anisotropism:Weak
Reflectivity:
400nmR=32.8%
420nmR=32.9%
440nmR=33.0%
460nmR=33.1%
480nmR=33.0%
500nmR=32.7%
520nmR=32.0%
540nmR=31.2%
560nmR=30.5%
580nmR=29.9%
600nmR=29.2%
620nmR=28.7%
640nmR=28.2%
660nmR=27.6%
680nmR=27.0%
700nmR=26.4%


Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 33.1%.

Chemical Properties of Acanthite

Formula:
Ag
 
2
S
Essential elements:Ag, S
All elements listed in formula:Ag, S
CAS Registry number:21548-73-2

CAS Registry numbers are published by the American Chemical Society
Common Impurities:Se

Relationship of Acanthite to other Species

Common Associates:
StephaniteSphaleriteSilverQuartzPyrargyrite
ProustitePolybasiteGalenaChalcopyriteCalcite
Aguilarite
Related Minerals - Nickel-Strunz Grouping):

- +
2.BA.05Chalcocite
Cu
 
2
S
2.BA.05Djurleite
Cu
 
31
S
 
16
2.BA.05Geerite
Cu
 
8
S
 
5
2.BA.05Roxbyite
Cu
 
9
S
 
5
2.BA.10Anilite
Cu
 
7
S
 
4
2.BA.10Digenite
Cu
 
9
S
 
5
2.BA.15Bornite
Cu
 
5
FeS
 
4
2.BA.20Bellidoite
Cu
 
2
Se
2.BA.20Berzelianite
Cu
 
2
Se
2.BA.25Athabascaite
Cu
 
5
Se
 
4
2.BA.25Umangite
Cu
 
3
Se
 
2
2.BA.30Rickardite
Cu
 
7
Te
 
5
2.BA.30Weissite
Cu
 
2-x
Te
2.BA.40Mckinstryite
Ag
 
5-x
Cu
 
3+x
S
 
4
2.BA.40Stromeyerite
AgCuS
2.BA.40dUM2003-13-S:AgAuCu
Ag
 
6
AuCu
 
2
S
 
5
2.BA.45Jalpaite
Ag
 
3
CuS
 
2
2.BA.45Selenojalpaite
Ag
 
3
CuSe
 
2
2.BA.50Eucairite
AgCuSe
2.BA.55Aguilarite
Ag
 
4
SeS
2.BA.55Naumannite
Ag
 
2
Se
2.BA.60Cervelleite
Ag
 
4
TeS
2.BA.60Hessite
Ag
 
2
Te
2.BA.60Chenguodaite
Ag
 
9
Fe
3+
 
Te
 
2
S
 
4
2.BA.65Henryite
Ag
 
3
Cu
 
4
Te
 
4
2.BA.65Stützite
Ag
 
5-x
Te
 
3
, x = 0.24-0.36
2.BA.70Argyrodite
Ag
 
8
GeS
 
6
2.BA.70Canfieldite
Ag
 
8
SnS
 
6
2.BA.70Putzite
(Cu
 
4.7
Ag
 
3.3
)GeS
 
6
2.BA.75Fischesserite
Ag
 
3
AuSe
 
2
2.BA.75Penzhinite
(Ag,Cu)
 
4
Au(S,Se)
 
4
2.BA.75Petrovskaite
AuAg(S,Se)
2.BA.75Petzite
Ag
 
3
AuTe
 
2
2.BA.75Uytenbogaardtite
Ag
 
3
AuS
 
2
2.BA.80Bezsmertnovite
(Au,Ag)
 
4
Cu(Te,Pb)
2.BA.80Bilibinskite
PbCuAu
 
3
Te
 
2
2.BA.80Bogdanovite
(Au,Te,Pb)
 
3
(Cu,Fe)
Related Minerals - Hey's Index Grouping:

- +
3.2.3Naumannite
Ag
 
2
Se
3.2.4Aguilarite
Ag
 
4
SeS
3.2.5Hessite
Ag
 
2
Te
3.2.6Empressite
AgTe
3.2.7Stützite
Ag
 
5-x
Te
 
3
, x = 0.24-0.36
3.2.8Cervelleite
Ag
 
4
TeS
3.2.9Dervillite
Ag
 
2
AsS
 
2
3.2.10Stromeyerite
AgCuS
3.2.11Mckinstryite
Ag
 
5-x
Cu
 
3+x
S
 
4
3.2.12Jalpaite
Ag
 
3
CuS
 
2
3.2.13Eucairite
AgCuSe
3.2.14Cameronite
AgCu
 
7
Te
 
10
3.2.15Henryite
Ag
 
3
Cu
 
4
Te
 
4
3.2.16Sternbergite
AgFe
 
2
S
 
3
3.2.17Argentopyrite
AgFe
 
2
S
 
3
3.2.18Geffroyite
(Cu,Fe,Ag)
 
9
(Se,S)
 
8
3.2.19Argentopentlandite
Ag(Fe,Ni)
 
8
S
 
8

Other Names for Acanthite

Synonyms:
AcantiteAkanthiteα-ArgentiteArgentiteArgentite-beta
Argentite-βArgyriteArgyroseBeta-Argentiteβ-Argentite
DaleminziteHenkelitePara-SilberglanzSilver GlanceVitreous Silver
Weicherz
Other Languages:
Anglo-Saxon:Argentite
Catalan:Argentita
Croatian:Argentit
Dutch:Argentiet
French:Acanthite
German:Argentit
Acanthit
Akanthit
α-Argentit
Argyrit
β-Argentit
Glanzerz
Glaserz
Henkelit
Silberglanz
Silberschwärze
Hungarian:Argentit
Italian:Argentite
Japanese:輝銀鉱
Latvian:Argentīts
Lithuanian:Argentitas
Low Saxon:Argentit
Polish:Argentyt
Russian:Аргентит
Simplified Chinese:螺状硫银矿
辉银矿
Slovak:Argentit
Spanish:Argentita
Acanthita
Akanthita
α-Argentita
Argyrita
β-Argentita
Henkelita
Swedish:Silverglans
Traditional Chinese:螺狀硫銀礦
Ukrainian:Аргентит
Varieties:
Zincian Acanthite

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
External LinksSearch for toxicity information at the United States National Library of Medicine

References for Acanthite

Reference List:

- +
Palache, Charles, Harry Berman & Clifford Frondel (1944) The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Volume I: Elements, Sulfides, Sulfosalts, Oxides. John Wiley and Sons, Inc., New York. 7th edition, revised and enlarged, 834pp.: 191-192.

Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften (1855) IV, 447-468.

Frueh, A. J. (1957) The crystal structure, polymorphism and twinning of acanthite (Ag2S). Acta Crystallographica, 10, 764-764.

Frueh, A. J. (1958) The crystallography of silver sulfide, Ag2S. Zeitschrift für Kristallographie, 110, 136-144.

Sadanaga, R. & Sueno, S. (1967) Mineral. J. (Japan), 5, 124.

Petruk, W.; Owens, D. R.; Stewart, J. M.; Murray, E. J. (1974) Observations on acanthite, aguilarite and naumannite. Canadian Mineralogist, 12, 365-369.
Dana's New Mineralogy, 8th Edition, Gaines et.al., p. 42.

Cava, R. J., Reidinger, F. & Wuensch, B. J. (1980) Single-crystal neutron diffraction study of the fast-ion conductor β-Ag2S between 186 and 325°C. Journal of Solid State Chemistry, 31, 69-80.

Mindat.org articles about Acanthite

Article entries:
Acanthite from MěděnecRobert Vaňo

Best Localities for Acanthite

Best of Species:Acanthite

Internet Links for Acanthite

Search Engines:
  • Look for Acanthite on Google
  • Look for Acanthite images on Google
    • External Links:
  • Look for Acanthite on Webmineral
  • Look for Acanthite on Athena Mineralogy
  • Look for Acanthite on Wikipedia
  • Look for Acanthite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Acanthite details from Handbook of Mineralogy (PDF)
    • Mineral Dealers:
  • webminerals
  • Search for Acanthite on Well-Arranged Molecules
  • Search for minerals at Heliodor
  • Fine Minerals from Weinrich Minerals, Inc.
  • Buy RARE Minerals from Rocks of Africa
  • Rare and Unusual minerals at Mineralogical Research Company
  • Buy from David K Joyce minerals
  • Find Acanthite on www.crystalclassics.co.uk
  • Buy fine minerals and gemstones from Pala International
  • Mineral Classics - Worldwide Collector Quality Minerals and Gems
  • Top quality minerals from Kristalle of California
  • DAKOTA MATRIX offers Cabinet and Rare Species from Worldwide Localities.
    • Specimens:The following Acanthite specimens are currently listed for sale on minfind.com.
    Jobs:
  • Mining & Geology Jobs

    • Localities for Acanthite

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
    Show Locality List (2525 Items)
    Mineral and/or Locality
    Search Google
     
    Copyright © Jolyon Ralph and Ida Chau 1993-2013. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Further information contact the Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of hundreds of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
    Current server date and time: 30th Mar 2013 09:55:36
    Mineral and Locality Search
    Mineral:
    and/or Locality:
    Options
    Fade toolbar when not in focusFix toolbar to bottom of page
    Hide Social Media Links
    Slideshow frame delay seconds
    Locality Updated: Peñas Azules Deposit, Sierra Calchaquí, Amaicha del Valle District, Tafí del Valle Department, Tucumán, ArgentinaFrom Raúl Jorge Tauber Larry, 19th May 2013 23:36:35