| |
 |
Laphamite Mineral Data
|
|
|
General Laphamite Information
|
 Chemical Formula: |
As2(Se,S)3 |
| Composition: |
Molecular Weight = 351.55 gm |
| |
Arsenic 42.62 % As |
| |
Selenium 50.54 % Se |
| |
Sulfur 6.84 % S |
| |
______ |
| |
100.00 % |
| Empirical Formula: |
As2Se2.25S0.75 |
| Environment: |
Secondary mineral formed as a sublimation product of a burning anthracite coal mine waste dump fire. |
| IMA Status: |
Approved IMA 1986 |
| Locality: |
Burnside, Northumberland County, Pennsylvania, USA. Link to MinDat.org Location Data. |
| Name Origin: |
Named for Davis M. Lapham (1931-1974), former Chief Mineralogist of the Pennsylvania Geological Survey. |
| Name Pronunciation: |
Laphamite + Pronunciation  |
| Synonym: |
ICSD 29535 |
| |
PDF 26-123 |
| |
Laphamite Image |
|
Images:
|
|
Laphamite Crystallography
|
| Axial Ratios: |
a:b:c =1.2156:1:0.4371 |
| Cell Dimensions: |
a = 11.86, b = 9.756, c = 4.265, Z = 4; beta = 90.17° V = 493.48 Den(Calc)= 4.73 |
| Crystal System: |
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 21/n |
| X Ray Diffraction: |
By Intensity(I/Io): 2.833(1), 2.773(0.8), 4.87(0.7), |
| |
Physical Properties of Laphamite
|
| Cleavage: |
{010} Perfect |
| Color: |
Dark red. |
| Density: |
4.5 |
| Diaphaneity: |
Translucent to Subopaque |
| Fracture: |
Flexible - Flexible fragments. |
| Habit: |
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline). |
| Hardness: |
1-2 - Between Talc and Gypsum |
| Luster: |
Resinous |
| Streak: |
red orange |
| |
Optical Properties of Laphamite
|
| RL Anisotrophism: |
Moderate, in tints of gray. |
| RL Color: |
Gray-white, strong fiery red internal reflections, golden yellow near scratches. |
| RL Pleochroism: |
Moderate, from white to gray. |
| Reflectivity |
Standardized Intensity (100%) Reflection Spectra of Laphamite in Air
| λ |
R1 |
R2 |
 |
∑ R1(λ) |
∑ R2(λ) |
| 400 nm |
34.40 |
42.10 |
|
|
|
| 420 nm |
33.90 |
41.00 |
|
| 440 nm |
33.80 |
39.90 |
|
| 460 nm |
33.80 |
38.80 |
|
| 480 nm |
33.20 |
37.40 |
|
| 500 nm |
32.30 |
36.30 |
|
| 520 nm |
30.90 |
35.10 |
|
| 540 nm |
29.50 |
34.00 |
|
| 560 nm |
28.40 |
33.10 |
|
| 580 nm |
27.60 |
32.30 |
|
| 600 nm |
26.90 |
31.60 |
|
| 620 nm |
26.40 |
31.10 |
|
| 640 nm |
26.40 |
30.90 |
|
| 660 nm |
26.30 |
30.60 |
|
| 680 nm |
26.10 |
30.40 |
|
| 700 nm |
25.90 |
30.10 |
|
Calculated Relative Intensity Colors of Laphamite in Air
Relative
Intensity |
0% |
40% |
80% |
100% |
120% |
160% |
200% |
240% |
280% |
320% |
| R1 |
|
|
|
|
|
|
|
|
|
|
| R2 |
|
|
|
|
|
|
|
|
|
|
|
| |
Calculated Properties of Laphamite
|
| Electron Density: |
Bulk Density (Electron Density)=4.16 gm/cc
note: Specific Gravity of Laphamite =4.73 gm/cc.
|
| Fermion Index: |
Fermion Index = 0.03
Boson Index = 0.97 |
| Photoelectric: |
PELaphamite = 72.06 barns/electron
U=PELaphamite x rElectron Density= 299.59 barns/cc.
|
| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Laphamite is Not Radioactive |
| |
Laphamite Classification
|
| Dana Class: |
02.11.06.01 (02)Sulfides - Including Selenides and Tellurides |
| |
(02.11)where Am Bn Xp, with (m+n):p=2:3 |
| |
(02.11.06)Dana Group |
| |
02.11.06.01 Laphamite As2(Se,S)3 P 21/n 2/m |
| Strunz Class: |
02.FA.30 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf |
| |
02.F - Sulfides of Arsenic, Alkalies; Sulfides with Halide, Oxide, Hydroxide, H2O |
| |
02.FA -With As, (Sb), S |
| |
02.FA.30 Orpiment As2S3 P 21/n 2/m |
| |
02.FA.30 Laphamite As2(Se,S)3 P 21/n 2/m |
| |
Other Laphamite Information
|
| References: |
NAME( AntBidBlaNic1) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1) |
| See Also: |
Links to other databases for Laphamite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
Search for Laphamite using:
[AOL]
[Bing]
[Dog Pile]
[GeoScienceWorld]
[HotBot]
[Ixquick]
[Lycos]
[MAMMA]
[Scirus]
[Teoma]
[WebCrawler]
[Wikipedia]
[YAHOO]
Visit our Advertisers for Laphamite :
Ask about Laphamite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in
Espaņol
Print or Cut-and-Paste your Laphamite Specimen Label here :
|
Laphamite
As2(Se,S)3
Dana No: 02.11.06.01 Strunz No: 02.FA.30
Locality:
Notes:
|
|
| |
| |
|
| |
Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.
