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Laphamite

This page kindly sponsored by Donald Lapham
Davis M. Lapham
Formula:
As2(Se,S)3
Colour:
dark red
Lustre:
Resinous
Hardness:
1 - 2
Crystal System:
Monoclinic
Name:
Named in honor of Davis M. Lapham (5 May 1931, Glens Falls, New York, USA - 20 December 1974, Harrisburg, Pennsylvania, USA), former Chief Mineralogist of the Pennsylvania Geological Survey. In addition to his technical work, he wrote several collector-friendly publications including 'Mineral Collecting in Pennsylvania'. He was a founding member of the Friends of Mineralogy.
Isostructural with:
The Se analogue of orpiment. Compare kalgoorlieite - the chemical (Te) analogue, but not isostructural with laphamite.

Caveat: Some (or all?) of the photographs showing yellow acicular material might depict Se-bearing orpiment rather than laphamite. (See discussion at https://www.mindat.org/forum.php?read,7,361533,391404#msg-391404 )


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Classification of LaphamiteHide

Approved
Approval Year:
1985
First Published:
1986
2.FA.30

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
2.11.6.1

2 : SULFIDES
11 : AmBnXp, with (m+n):p = 2:3
3.7.10

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

Physical Properties of LaphamiteHide

Resinous
Transparency:
Opaque
Colour:
dark red
Streak:
red-orange
Hardness:
1 - 2 on Mohs scale
Cleavage:
Perfect

Chemical Properties of LaphamiteHide

Formula:
As2(Se,S)3
IMA Formula:
As2Se3

Crystallography of LaphamiteHide

Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 11.86 Å, b = 9.75 Å, c = 4.26 Å
β = 90.17°
Ratio:
a:b:c = 1.216 : 1 : 0.437
Unit Cell V:
492.60 ų (Calculated from Unit Cell)
Comment:
P21/n

Type Occurrence of LaphamiteHide

Place of Conservation of Type Material:
The Natural History Museum, London, England, 1984,843 and E.1036.
National Museum of Natural History (Smithsonian), Washington, D.C., USA, 163039.
Geological Setting of Type Material:
Secondary mineral formed, probably by sublimation, on a clinker adjacent to a surface vent on a burning pile of coal.
Reference:
Dunn, P.J., Peacor, D.R., Criddle, A.J., Finkelman, R.B. (1986) Laphamite, an arsenic selenide analogue of orpiment, from burning anthracite deposits in Pennsylvania. Mineralogical Magazine: 50: 279-282.

Synonyms of LaphamiteHide

Other Language Names for LaphamiteHide

German:Laphamit
Spanish:Laphamita

Common AssociatesHide

Associated Minerals Based on Photo Data:
Orpiment2 photos of Laphamite associated with Orpiment on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

2.FA.AnorpimentAs2S3Tric. 1 : P1
2.FA.BonazziiteAs4S4Mon. 2/m : B2/b
2.FA.05DuranusiteAs4SOrth. mmm (2/m 2/m 2/m) : Pmna
2.FA.10DimorphiteAs4S3Orth. mmm (2/m 2/m 2/m) : Pnma
2.FA.15bPararealgarAs4S4Mon. 2/m : P21/b
2.FA.15aRealgarAs4S4Mon. 2/m
2.FA.15dUM1970-18-S:AsAs4S4Mon. 2/m : B2/b
2.FA.20AlacrániteAs8S9Mon. 2/m : P2/b
2.FA.25UzoniteAs4S5Mon.
2.FA.30OrpimentAs2S3Mon. 2/m
2.FA.35GetchelliteAsSbS3Mon. 2/m : P21/b
2.FA.40Wakabayashilite[(As,Sb)6S9][As4S5]Orth. mm2 : Pna21

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

3.7.1PatróniteVS4Mon.
3.7.2DuranusiteAs4SOrth. mmm (2/m 2/m 2/m) : Pmna
3.7.3DimorphiteAs4S3Orth. mmm (2/m 2/m 2/m) : Pnma
3.7.4RealgarAs4S4Mon. 2/m
3.7.5PararealgarAs4S4Mon. 2/m : P21/b
3.7.6AlacrániteAs8S9Mon. 2/m : P2/b
3.7.7UzoniteAs4S5Mon.
3.7.8OrpimentAs2S3Mon. 2/m
3.7.9JeromiteAmor.
3.7.11GetchelliteAsSbS3Mon. 2/m : P21/b
3.7.12Wakabayashilite[(As,Sb)6S9][As4S5]Orth. mm2 : Pna21
3.7.13PääkköneniteSb2AsS2Mon. 2/m : B2/m
3.7.14StibniteSb2S3Orth. mmm (2/m 2/m 2/m)
3.7.15MetastibniteSb2S3Amor.
3.7.16TellurantimonySb2Te3Trig.
3.7.17BismuthiniteBi2S3Orth. mmm (2/m 2/m 2/m)
3.7.18NevskiteBi(Se,S)Trig.
3.7.19GuanajuatiteBi2Se3Orth. mmm (2/m 2/m 2/m) : Pnma
3.7.21IkunoliteBi4(S,Se)3Trig.
3.7.22LaitakariteBi4Se2STrig. 3m : R3m
3.7.23PoubaitePbBi2(Se,Te,S)4Trig.
3.7.24TellurobismuthiteBi2Te3Trig.
3.7.25SoučekitePbCuBi(S,Se)3Orth.
3.7.26TsumoiteBiTeTrig. 3m (3 2/m) : P3 1m
3.7.27PilseniteBi4Te3Trig. 3m (3 2/m) : R3m
3.7.28HedleyiteBi7Te3Trig. 3m (3 2/m) : R3m
3.7.29TetradymiteBi2Te2STrig. 3m (3 2/m) : R3m
3.7.30JoséiteBi4TeS2Trig. 3m (3 2/m) : R3m
3.7.31Joséite-BBi4Te2STrig.
3.7.32IngoditeBi2TeSTrig.
3.7.33SulphotsumoiteBi3Te2STrig.
3.7.34KawazuliteBi2Te2SeTrig.
3.7.36SkippeniteBi2TeSe2Trig.
3.7.37KochkaritePbBi4Te7Trig.
3.7.38RucklidgeitePbBi2Te4Trig.
3.7.39AleksitePbBi2Te2S2Trig.
3.7.40JunoiteCu2Pb3Bi8(S,Se)16Mon. 2/m : B2/m

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for LaphamiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Kirkinskii, V.A., Yakushev, V.G. (1968) A new polymorphic modification of arsenic selenide obtained at high pressures (in English). Doklady Chemistry: 182: 896-898.
Kirkinskii, V.A., Yakushev, V.G. (1968) A new polymorphic modification of arsenic selenide obtained at high pressures (in Russian). Doklady Akademii Nauk SSSR: 182: 1083-1086.
Kirkinskii, V.A., Ryaposov, A.P., Yakushev, V.G. (1970) Synthesis of a third polymorphic modification of arsenic selenide at high pressure. Soviet Physics Solid State, USSR: 11: 1923-1924.
Zallen, R., Slade, M.L., Ward, A.T. (1971) Lattice vibrations and interlayer interactions in crystalline As2S3 and As2Se3. Physical Review B: 3: 4257-4273.
Stergiou, A.C., Rentzeperis, P.J. (1986) The crystal structure of arsenic selenide, As2Se3. Zeitschrift für Kristallographie: 173: 185–191.
Dunn, P.J., Peacor, D.R., Criddle, A.J., Finkelman, R.B. (1986) Laphamite, an arsenic selenide analogue of orpiment, from burning anthracite deposits in Pennsylvania. Mineralogical Magazine: 50: 279-282.
Hawthorne, F.C., Jambor, J.L., Bladh, K.W., Burke, E.A.J., Grice, J.D., Phillips, D., Roberts, A.C., Schedler, R.A., Shigley, J.E. (1987) New mineral names. American Mineralogist: 72: 1023-1028.
Bindi, L., Bonazzi, P., Spry, P.G. (2008) Effects of sulfur-for-selenium substitution on the structure of laphamite, As2(Se,S)3. The Canadian Mineralogist: 46: 269-274.
Anthony, J.W., Bideaux, R.A., Bladh, K.W., Nichols, M.C., Eds. Handbook of Mineralogy, Mineralogical Society of America, Chantilly, VA 20151-1110, USA. http://www.handbookofmineralogy.org/ (2016)

Internet Links for LaphamiteHide

Localities for LaphamiteHide

This 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.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for 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 (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
USA (TL)
 
  • Pennsylvania
    • Northumberland Co.
Mineralogical Magazine: 50:279 (1986), Dunn, et al.
Mineral and/or Locality  
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