Larsenite
A valid IMA mineral species - grandfathered
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About Larsenite
Esper Signius Larsen, Jr
Formula:
PbZnSiO4
Colour:
Colorless, white
Lustre:
Sub-Adamantine, Vitreous, Sub-Vitreous, Silky
Hardness:
3
Specific Gravity:
5.90
Crystal System:
Orthorhombic
Name:
Named in 1928 by Charles Palache, Lawson Henry Bauer, and Harry Berman in honor of Esper Signius Larsen, Jr. [March 14, 1879 Astoria, Oregon, USA - March 8, 1961 Washington, DC, USA], petrologist and Professor of Geology at Harvard University, Cambridge, Massachusetts, USA. The mineral esperite is also named after him.
Type Locality:
A very rare lead silicate found on fracture surfaces and in cavities in massive ore. It occurs in bright colorless to cloudy white, usually free-standing groups of acicular to bladed crystals, and has a very high luster. Chlorophoenicite has been frequently confused with larsenite, but larsenite is almost universally found with other lead silicates. Palache (1935) stated: "Larsenite is far less abundant than calcium larsenite [esperite], and in most specimens the two are not associated, but in two places crystals of larsenite were found in cavities with calcium larsenite." Subsequently, larsenite has been found with a wider variety of species. At the type location, larsenite is a vein filling mineral associated with lead silicates, particularly with esperite and clinohedrite. Crystals have an adamantine to sub-adamantine luster and are visibly longitudinally striated. Larsenite DOES NOT fluoresce in shortwave, midwave, or longwave ultraviolet light. Historically, chlorophoenicite, aragonite, and other white acicular crystals have often mistaken for larsenite, although the ordinary physical appearance is usually enough to distinguish then. Unfortunately, a great many mis-labeled specimens persist in the marketplace, often with accompanying labels from famous collections, including those of museums. Larsenite has yet to be found at the Sterling Mine on Sterling hill. Larsenite is a considerable rarity.
Unique Identifiers
Mindat ID:
2335
Long-form identifier:
mindat:1:1:2335:7
Similar Names
| Arsenite | A synonym of Arsenolite | |
| Lausenite | A valid IMA mineral species - grandfathered | Fe2(SO4)3 · 5H2O |
IMA Classification of Larsenite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Pb2+Zn2+SiO4
Classification of Larsenite
9.AB.10
9 : SILICATES (Germanates)
A : Nesosilicates
B : Nesosilicates without additional anions; cations in [4] and greater coordination
9 : SILICATES (Germanates)
A : Nesosilicates
B : Nesosilicates without additional anions; cations in [4] and greater coordination
Dana 7th ed.:
51.2.1.2
51.2.1.2
51 : NESOSILICATES Insular SiO4 Groups Only
2 : Insular SiO4 Groups Only with cations in [4] as well as >[4]
51 : NESOSILICATES Insular SiO4 Groups Only
2 : Insular SiO4 Groups Only with cations in [4] as well as >[4]
14.7.18
14 : Silicates not Containing Aluminum
7 : Silicates of Ba, Sr and Zn
14 : Silicates not Containing Aluminum
7 : Silicates of Ba, Sr and Zn
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Lsn | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Larsenite
Sub-Adamantine, Vitreous, Sub-Vitreous, Silky
Transparency:
Transparent
Colour:
Colorless, white
Streak:
White
Hardness:
3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
Good on {120}
Good on {120}
Fracture:
Irregular/Uneven
Density:
5.90 g/cm3 (Measured) 6.12 g/cm3 (Calculated)
Optical Data of Larsenite
Type:
Biaxial (-)
RI values:
nα = 1.92 nβ = 1.95 nγ = 1.96
2V:
Measured: 80° , Calculated: 58°
Birefringence:
0.04
Max. Birefringence:
δ = 0.040
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
r > v easily perceptible
Optical Extinction:
Parallel
Pleochroism:
Non-pleochroic
Comments:
X=a, Y=c, Z=b, strong absorption
Chemistry of Larsenite
Mindat Formula:
PbZnSiO4
Element Weights:
Elements listed:
Common Impurities:
Fe,Mn,Mg,Ca,H2O
Crystallography of Larsenite
Crystal System:
Orthorhombic
Class (H-M):
mm2 - Pyramidal
Space Group:
Pna21
Setting:
Pna21
Cell Parameters:
a = 8.24 Å, b = 18.96 Å, c = 5.06 Å
Ratio:
a:b:c = 0.435 : 1 : 0.267
Unit Cell V:
790.53 ų (Calculated from Unit Cell)
Z:
8
Morphology:
Slender prismatic to acicular [001]?, sometimes tabular to bladed {010}. Originally found in specimens where both habits were present.
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
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Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
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CIF File Best | x | y | z | a | b | c
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0010633 | Larsenite | Prewitt C T, Kirchner E, Preisinger A (1967) Crystal structure of larsenite PbZnSiO4 Zeitschrift fur Kristallographie 124 115-130 |  | 1967 | Franklin, New Jersey, USA | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.50 Å | (10) |
| 6.23 Å | (6) |
| 4.88 Å | (80) |
| 4.75 Å | (20) |
| 4.19 Å | (60) |
| 4.11 Å | (50) |
| 4.03 Å | (50) |
| 2.97 Å | (2) |
| 3.93 Å | (10) |
| 3.78 Å | (30) |
| 3.56 Å | (16) |
| 3.45 Å | (20) |
| 3.19 Å | (100) |
| 3.15 Å | (10) |
| 3.11 Å | (16) |
| 3.04 Å | (80) |
| 2.955 Å | (6) |
| 2.854 Å | (90) |
| 2.793 Å | (30) |
| 2.720 Å | (30) |
| 2.651 Å | (4) |
| 2.576 Å | (8) |
| 2.525 Å | (25) |
| 2.442 Å | (2) |
| 2.395 Å | (4) |
| 2.376 Å | (6) |
| 2.341 Å | (4) |
| 2.295 Å | (2) |
| 2.294 Å | (8) |
| 2.230 Å | (8) |
| 2.150 Å | (10) |
| 2.100 Å | (6) |
| 2.080 Å | (6) |
| 2.075 Å | (6) |
| 2.068 Å | (8) |
| 2.064 Å | (8) |
| 2.057 Å | (6) |
| 2.053 Å | (8) |
| 2.044 Å | (6) |
| 2.039 Å | (10) |
| 2.014 Å | (6) |
| 1.975 Å | (6) |
| 1.961 Å | (10) |
| 1.932 Å | (25) |
| 1.917 Å | (8) |
| 1.894 Å | (10) |
| 1.872 Å | (16) |
| 1.850 Å | (10) |
| 1.828 Å | (8) |
| 1.802 Å | (4) |
Comments:
ICDD 20-607, 20-607a (synthetic)
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits |
Type Occurrence of Larsenite
General Appearance of Type Material:
Colorless, acicular to long-prismatic or bladed striated crystals.
Place of Conservation of Type Material:
Harvard University
Geological Setting of Type Material:
A very rare secondary mineral in vugs usually associated with esperite and clinohedrite. The assemblage is composed of lead-rich silicates whcih are the result of hydrothermal alteration cutting coarse, massive willemite-franklinite ore in a stratiform, Precambrian Zn-Mn-Fe deposit
Associated Minerals at Type Locality:
Synonyms of Larsenite
Other Language Names for Larsenite
Common Associates
Associations Based on Photo Data:
| 6 photos of Larsenite associated with Willemite | Zn2SiO4 |
| 5 photos of Larsenite associated with Clinohedrite | CaZn(SiO4) · H2O |
| 2 photos of Larsenite associated with Hodgkinsonite | Mn2+Zn2(SiO4)(OH)2 |
| 1 photo of Larsenite associated with Franklinite | Zn2+Fe3+2O4 |
| 1 photo of Larsenite associated with Zincite | ZnO |
Related Minerals - Strunz-mindat Grouping
| 9.AB.05 | Trimerite | CaMn2+2Be3(SiO4)3 |
| 9.AB.15 | Esperite | PbCa2Zn3(SiO4)3 |
| 9.AB.20 | Rondorfite | Ca8Mg(SiO4)4Cl2 |
Fluorescence of Larsenite
Not fluorescent in UV.
Other Information
Health Risks:
Contains lead.
Internet Links for Larsenite
mindat.org URL:
https://www.mindat.org/min-2335.html
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Please feel free to link to this page.
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References for Larsenite
Reference List:
Palache, C., Bauer, L. H., Berman, H. (1928) Larsenite and calcium-larsenite, new members of the chrysolite group, from Franklin, New Jersey. (Preliminary Notice) American Mineralogist, 13 (4) 142-144
Palache, C., Bauer, L. H., Berman, H. (1928) Larsenite, calcium-larsenite and associated minerals at Franklin, New Jersey. American Mineralogist, 13 (7) 334-340
Palache, Charles (1935) The minerals of Franklin and Sterling Hill, Sussex County, New Jersey. Professional Paper 180. US Geological Survey 135 pp. doi:10.3133/pp180
Layman, Frederic G. (1957) Unit cell and space group of larsenite, PbZnSiO4. American Mineralogist, 42 (11-12) 910-911
Ito, Jun, Frondel, Clifford (1967) Syntheses of lead silicates: larsenite, barysilite and related phases. American Mineralogist, 52 (7-8) 1077-1084
Prewitt, C. T.; Kirchner, E.; Preisinger, A. (1967) Crystal structure of larsenite PbZnSiO4. Zeitschrift für Kristallographie, 124 (1-2). 115-130 doi:10.1524/zkri.1967.124.1-2.115
Ito, Jun (1968) Synthesis of some lead calcium zinc silicates. American Mineralogist, 53 (1-2) 231-240
Localities for Larsenite
Showing 7 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - 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).
All localities listed without proper references should be considered as questionable.
Australia | |
| Muller (1972) +1 other reference |
Germany | |
| Schnorrer-Köhler (1989) |
India | |
| Ahmed et al. (2018) |
Mexico | |
| Parker (2010) |
Namibia | |
| Gebhard (1999) |
USA (TL) | |
| Palache (1935) +1 other reference |
| Palache et al. (1928) +2 other references |
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Franklin Mine, Franklin, Sussex County, New Jersey, USA