Kennygayite
A valid IMA mineral species
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About Kennygayite
Kenny Gay
Formula:
[Pb4O2(OH)2](SO4)
Colour:
colorless to pale yellow
Lustre:
Adamantine
Hardness:
2½
Specific Gravity:
7.078 (Calculated)
Crystal System:
Triclinic
Name:
The name kennygayite is for American geologist, geoscience educator and mineral collector Norman Kennedy (Kenny) Gay (b. 1953, d. 2023). Mr. Gay had a 40+ year career as a licensed, professional geologist and was employed with the North Carolina Geological Survey since 1995, and a member of the adjunct faculty at Wesleyan College, Rocky Mount, North Carolina, as a professor of geology since 2001. In addition to his contributions to numerous abstracts and papers on the Geology and Mineralogy of North Carolina, Mr. Gay has held leadership roles in several geology and mineralogy clubs since 1990. He has built a large collection of worldwide minerals, but his main focus is on the mineralogy of North Carolina. He has extensively catalogued all known important North Carolina mineral occurrences along with the history of mineral collecting and mining in the state. Among the mineral occurrences that he has examined and collected is the Redmond mine. Although Mr. Gay is not responsible for the discovery of the unique mineral assemblage that has produced so many new species, including kennygayite, he was one of the first to collect mineral specimens at the mine and he got one of the authors (JBS) interested in the mine, thereby leading to the discovery of this assemblage.
The sulfate analogue of the thiosulphate mineral sidpietersite.
Chemically resembles leadhillite, susannite, among others.
Chemically resembles leadhillite, susannite, among others.
Unique Identifiers
Mindat ID:
56159
Long-form identifier:
mindat:1:1:56159:8
IMA Classification of Kennygayite
Approved
IMA Formula:
[Pb2+4O2(OH)2](S6+O4)
Approval history:
IMA no. 2022-032
Type description reference:
Kampf, Anthony R.; Smith, Jason B.; Hughes, John M.; Ma, Chi; Emproto, Christopher (2024) New Minerals from the Redmond Mine, North Carolina, USA: VI. Boojumite and Kennygayite, Two New Minerals with Structures Based on Chains of Oxocentered OPb4 TETRAHEDRA. The Canadian Journal of Mineralogy and Petrology, 62 (2). doi:10.3749/2300051
Classification of Kennygayite
7.BD.
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
B : Sulfates (selenates, etc.) with additional anions, without H2O
D : With only large cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
B : Sulfates (selenates, etc.) with additional anions, without H2O
D : With only large cations
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 |
|---|---|---|
| Kgy | 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 Kennygayite
Adamantine
Colour:
Colorless to pale yellow
Streak:
White
Hardness:
2½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
{001}
{001}
Fracture:
Step-Like
Density:
7.078 g/cm3 (Calculated)
Optical Data of Kennygayite
Type:
Biaxial (-)
RI values:
nα = 1.98 nβ = 2.01 nγ = 2.09
2V:
Measured: 58° (5)
Max. Birefringence:
δ = 0.110
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.
Comments:
α = 1.98(calc.), β = 2.01 (est.), γ = 2.09 (calc.)
Chemistry of Kennygayite
Mindat Formula:
[Pb4O2(OH)2](SO4)
Element Weights:
Elements listed:
Crystallography of Kennygayite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 6.3785(5) Å, b = 7.4519(6) Å, c = 10.3112(8) Å
α = 75.234(5)°, β = 79.388(6)°, γ = 88.175(6)°
α = 75.234(5)°, β = 79.388(6)°, γ = 88.175(6)°
Ratio:
a:b:c = 0.856 : 1 : 1.384
Unit Cell V:
465.76 ų (Calculated from Unit Cell)
Z:
2
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 9.90 Å | (86) |
| 5.78 Å | (43) |
| 3.291 Å | (100) |
| 3.149 Å | (98) |
| 3.114 Å | (65) |
| 2.892 Å | (68) |
| 2.721 Å | (64) |
| 1.685 Å | (40) |
Reference:
Kampf, Anthony R.; Smith, Jason B.; Hughes, John M.; Ma, Chi; Emproto, Christopher (2024) New Minerals from the Redmond Mine, North Carolina, USA: VI. Boojumite and Kennygayite, Two New Minerals with Structures Based on Chains of Oxocentered OPb4 TETRAHEDRA. The Canadian Journal of Mineralogy and Petrology, 62 (2). doi:10.3749/2300051
Type Occurrence of Kennygayite
General Appearance of Type Material:
colorless to pale yellow wedges and lozenge-shaped wafers, up to about 1 mm across
Place of Conservation of Type Material:
mineralogical collections of the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue numbers 76229, 76230 and 76231 (cotypes)
Geological Setting of Type Material:
highly unusual secondary assemblage that comprises a variety of rare Pb-Zn-Cu sulfates, thiosulfates, and carbonates
Associated Minerals at Type Locality:
Reference:
Kampf, Anthony R.; Smith, Jason B.; Hughes, John M.; Ma, Chi; Emproto, Christopher (2024) New Minerals from the Redmond Mine, North Carolina, USA: VI. Boojumite and Kennygayite, Two New Minerals with Structures Based on Chains of Oxocentered OPb4 TETRAHEDRA. The Canadian Journal of Mineralogy and Petrology, 62 (2). doi:10.3749/2300051
Other Language Names for Kennygayite
Dutch:Kennygayiet
German:Kennygayit
Related Minerals - Strunz-mindat Grouping
| 7.BD. | Hasanovite | KNa(MoO2)(SO4)2 |
| 7.BD. | Adanite | Pb2(Te4+O3)(SO4) |
| 7.BD. | Cadsulfohite | Cd2(SO4)(OH)2 |
| 7.BD. | Hyblerite | Pb4Bi2(SO4)2(CO3)O4 |
| 7.BD. | Zanelliite | PbCu9[AsO3.5(OH)0.5]2(AsO4)2(OH)9(H2O)3 |
| 7.BD. | Evanichite | Pb6Cr3+(Cr6+O4)2(SO4)(OH)7FCl |
| 7.BD.05 | Sulphohalite | Na6(SO4)2FCl |
| 7.BD.10 | Galeite | Na15(SO4)5F4Cl |
| 7.BD.10 | Schairerite | Na21(SO4)7ClF6 |
| 7.BD.15 | Kogarkoite | Na3(SO4)F |
| 7.BD.20 | Aiolosite | Na4Bi(SO4)3Cl |
| 7.BD.20 | Caracolite | Na3Pb2(SO4)3Cl |
| 7.BD.20 | Cesanite | Na3Ca2(SO4)3(OH) |
| 7.BD.25 | Burkeite | Na6(CO3)(SO4)2 |
| 7.BD.30 | Hanksite | Na22K(SO4)9(CO3)2Cl |
| 7.BD.35 | Cannonite | Bi2(SO4)O(OH)2 |
| 7.BD.40 | Lanarkite | Pb2(SO4)O |
| 7.BD.45 | Grandreefite | Pb2(SO4)F2 |
| 7.BD.50 | Itoite | Pb3Ge4+(SO4)2O2(OH)2 |
| 7.BD.55 | Chiluite | Bi3Te6+Mo6+O10.5 |
| 7.BD.60 | Hectorfloresite | Na9(SO4)4(IO3) |
| 7.BD.65 | Pseudograndreefite | Pb6(SO4)F10 |
| 7.BD.70 | Sundiusite | Pb10(SO4)O8Cl2 |
Other Information
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 Kennygayite
mindat.org URL:
https://www.mindat.org/min-56159.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Kennygayite
Reference List:
Miyawaki, Ritsuro, Hatert, Frédéric, Pasero, Marco, Mills, Stuart J. (2022) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) – Newsletter 68. European Journal of Mineralogy, 34 (5) 385-391 doi:10.5194/ejm-34-385-2022
Kampf, Anthony R.; Smith, Jason B.; Hughes, John M.; Ma, Chi; Emproto, Christopher (2024) New Minerals from the Redmond Mine, North Carolina, USA: VI. Boojumite and Kennygayite, Two New Minerals with Structures Based on Chains of Oxocentered OPb4 TETRAHEDRA. The Canadian Journal of Mineralogy and Petrology, 62 (2). doi:10.3749/2300051
Localities for Kennygayite
Showing 2 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.
Germany | |
| EDS- |
USA (TL) | |
| Miyawaki et al. (2022) |
Redmond Mine, Waterville Lake, Haywood County, North Carolina, USA