Hardystonite
A valid IMA mineral species - grandfathered
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About Hardystonite
Formula:
Ca2Zn[Si2O7]
Colour:
Light brownish white, pale greyish-white, whitish, very pale pinkish
Lustre:
Adamantine, Resinous, Dull
Hardness:
3 - 4
Specific Gravity:
3.396 - 3.443
Crystal System:
Tetragonal
Member of:
Name:
Named in 1899 by John E. Wolff after Hardyston Township, Sussex County, New Jersey, USA, locality of the Franklin orebody prior to incorporation of Franklin Borough in 1913. Hardyston Township surrounds the borough of Franklin today.
Type Locality:
In daylight, natural hardystonite is a very non-descript massive ashen white mineral distinguished from massive calcite by a lack of cleavage and a somewhat greasy luster. (Note: Many photographers over-expose images of hardystonite to accentuate the blue fluorescent brightness. Such photos are often called "eBay blue", because deceptive sellers wish to increase their sales, but disappointed buyers feel cheated because the actual fluorescence of hardystonite is fairly dim compared with associated species such as calcite, willemite, or esperite.)
Visit gemdat.org for gemological information about Hardystonite.
Unique Identifiers
Mindat ID:
1818
Long-form identifier:
mindat:1:1:1818:6
GUID
(UUID V4):
(UUID V4):
b489739f-51de-46ca-9561-6e9bf5358379
IMA Classification of Hardystonite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Ca2ZnSi2O7
First published:
1899
Classification of Hardystonite
9.BB.10
9 : SILICATES (Germanates)
B : Sorosilicates
B : Si2O7 groups, without non-tetrahedral anions; cations in tetrahedral [4] and greater coordination
9 : SILICATES (Germanates)
B : Sorosilicates
B : Si2O7 groups, without non-tetrahedral anions; cations in tetrahedral [4] and greater coordination
55.4.2.2
55 : SOROSILICATES Si2O7 Groups,Generally with no Additional Anions
4 : Si2O7 Groups, Generally with No Additional Anions with cations in [8] and lower coordination
55 : SOROSILICATES Si2O7 Groups,Generally with no Additional Anions
4 : Si2O7 Groups, Generally with No Additional Anions with cations in [8] and lower coordination
14.7.14
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 |
---|---|---|
Hdy | 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 Hardystonite
Adamantine, Resinous, Dull
Transparency:
Opaque
Colour:
Light brownish white, pale greyish-white, whitish, very pale pinkish
Streak:
White
Hardness:
3 - 4 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
Good on {001}; poor on {100} and {110}.
Good on {001}; poor on {100} and {110}.
Density:
3.396 - 3.443 g/cm3 (Measured) 3.42 g/cm3 (Calculated)
Optical Data of Hardystonite
Type:
Uniaxial (-)
RI values:
nω = 1.672 nε = 1.661
Birefringence:
0.009
Max Birefringence:
δ = 0.011
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Moderate
Optical Extinction:
parallel
Pleochroism:
Non-pleochroic
Chemistry of Hardystonite
Mindat Formula:
Ca2Zn[Si2O7]
Elements listed:
Common Impurities:
Al,Fe,Mn,Pb,Mg,Na
Crystallography of Hardystonite
Crystal System:
Tetragonal
Class (H-M):
4 2m - Scalenohedral
Space Group:
P4 21m
Cell Parameters:
a = 7.8287(16) Å, c = 5.0140(2) Å
Ratio:
a:c = 1 : 0.64
Unit Cell V:
307.30 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Large, rough crystals rare embedded in calcite or other matrix.
Crystal Structure
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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) |
---|---|---|---|---|---|---|---|
0002657 | Hardystonite | Bindi L, Bonazzi P, Rothlisberger F (2001) Hardystonite from Franklin Furnace: A natural modulated melilite American Mineralogist 86 747-751 | 2001 | 0 | 293 | ||
0018114 | Hardystonite | Warren B, Trautz O (1930) The Structure of Hardystonite Ca2 Zn Si2 O7 _cod_database_code 1011252 Zeitschrift fur Kristallographie 75 525-528 | 1930 | 0 | 293 | ||
0010703 | Hardystonite | Louisnathan S J (1969) Refinement of the crystal structure of hardystonite, Ca2ZnSi2O7 Zeitschrift fur Kristallographie 130 427-437 | 1969 | Franklin, New Jersey, USA | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
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Radiation - Copper Kα
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
5.533 Å | (1) |
5.016 Å | (15) |
4.222 Å | (7) |
3.911 Å | (1) |
3.716 Å | (38) |
3.500 Å | (4) |
3.086 Å | (63) |
2.871 Å | (100) |
2.767 Å | (13) |
2.508 Å | (8) |
2.475 Å | (36) |
2.423 Å | (13) |
2.388 Å | (7) |
2.314 Å | (8) |
2.284 Å | (5) |
2.2195 Å | (8) |
2.1711 Å | (1) |
2.1113 Å | (1) |
2.0389 Å | (14) |
1.9564 Å | (2) |
1.8985 Å | (6) |
1.8585 Å | (11) |
1.8447 Å | (5) |
1.8231 Å | (3) |
1.8079 Å | (1) |
1.7757 Å | (12) |
1.7620 Å | (38) |
1.7503 Å | (19) |
1.7316 Å | (9) |
1.623 Å | (1) |
1.6524 Å | (6) |
1.6413 Å | (3) |
1.6351 Å | (1) |
1.6006 Å | (5) |
1.5369 Å | (6) |
1.5343 Å | (5) |
1.5133 Å | (3) |
1.5082 Å | (5) |
1.4943 Å | (1) |
1.4671 Å | (8) |
1.4526 Å | (1) |
1.4346 Å | (7) |
1.4306 Å | (7) |
1.4073 Å | (3) |
1.3954 Å | (7) |
1.3850 Å | (7) |
1.3419 Å | (1) |
1.3333 Å | (4) |
1.3274 Å | (1) |
1.3243 Å | (1) |
plus 25 lines to 1.0968 Å | (1) |
Comments:
ICDD 35-745, 35-745a
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
High-𝑇 alteration and/or metamorphism | |
32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits | |
Stage 10b: Anthropogenic minerals | <10 Ka |
56 : Slag and smelter minerals (see also #51 and #55) |
Type Occurrence of Hardystonite
General Appearance of Type Material:
In banded ore, forming grains averaging about a millimeter in diameter.
Place of Conservation of Type Material:
Harvard University, Cambridge, Massachusetts, USA, numbers 113594, 113608.
Geological Setting of Type Material:
Occurs in a metamorphosed zinc-manganese-iron silicate-oxide orebody.
Associated Minerals at Type Locality:
Other Language Names for Hardystonite
Relationship of Hardystonite to other Species
Member of:
Other Members of this group:
Åkermanite | Ca2Mg[Si2O7] | Tet. 4 2m : P4 21m |
Alumoåkermanite | (CaNa)Al[Si2O7] | Tet. 4 2m : P4 21m |
Bennesherite | Ba2Fe2+[Si2O7] | Tet. 4 2m : P4 21m |
Ferri-gehlenite | Ca2Fe3+[AlSiO7] | |
Gehlenite | Ca2Al[AlSiO7] | Tet. 4 2m : P4 21m |
Gugiaite | Ca2Be[Si2O7] | Tet. 4 2m : P4 2m |
Hydroxylgugiaite | (Ca,◻)2(Si,Be)[(Be,Si)2O5.5(OH)1.5] | Tet. 4 2m : P4 21m |
Okayamalite | Ca2B[BSiO7] | Tet. 4 2m : P4 21m |
Common Associates
Associated Minerals Based on Photo Data:
329 photos of Hardystonite associated with Willemite | Zn2SiO4 |
199 photos of Hardystonite associated with Franklinite | Zn2+Fe3+2O4 |
171 photos of Hardystonite associated with Calcite | CaCO3 |
167 photos of Hardystonite associated with Clinohedrite | CaZn(SiO4) · H2O |
82 photos of Hardystonite associated with Esperite | PbCa2Zn3(SiO4)3 |
36 photos of Hardystonite associated with Zincite | ZnO |
26 photos of Hardystonite associated with Andradite | Ca3Fe3+2(SiO4)3 |
18 photos of Hardystonite associated with Bustamite | CaMn2+(Si2O6) |
12 photos of Hardystonite associated with Diopside | CaMgSi2O6 |
11 photos of Hardystonite associated with Glaucochroite | CaMn2+SiO4 |
Related Minerals - Strunz-mindat Grouping
9.BB.10 | Åkermanite | Ca2Mg[Si2O7] |
9.BB.10 | Cebollite | Ca5Al2(SiO4)3(OH)4 |
9.BB.10 | Gehlenite | Ca2Al[AlSiO7] |
9.BB.10 | Gugiaite | Ca2Be[Si2O7] |
9.BB.10 | Jeffreyite | (Ca,Na)2(Be,Al)(Si2O7,HSi2O7) |
9.BB.10 | Okayamalite | Ca2B[BSiO7] |
9.BB.10 | Ferri-gehlenite | Ca2Fe3+[AlSiO7] |
9.BB.10 | Alumoåkermanite | (CaNa)Al[Si2O7] |
9.BB.10 | Hydroxylgugiaite | (Ca,◻)2(Si,Be)[(Be,Si)2O5.5(OH)1.5] |
9.BB.15 | Barylite | Be2Ba(Si2O7) |
9.BB.15 | Barylite-1O | Be2Ba(Si2O7) |
9.BB.20 | Andrémeyerite | BaFe2+2(Si2O7) |
9.BB.20 | Bennesherite | Ba2Fe2+[Si2O7] |
Fluorescence of Hardystonite
Dull persistent purple to blue (SW UV); blue (LW UV).
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.
Industrial Uses:
None, but a common constituent of zinc rich slags from smelting processes.
Internet Links for Hardystonite
mindat.org URL:
https://www.mindat.org/min-1818.html
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References for Hardystonite
Localities for Hardystonite
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).
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 (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
All localities listed without proper references should be considered as questionable.
Australia | |
| Parbhakar-Fox |
Czech Republic | |
| Pauliš P. Mineralogické lokality ... |
Germany | |
| Bender et al. (1994) |
| Neschen (n.d.) |
| Elmar Lackner collection |
Besteman | |
Mexico | |
| Espejel-Garcia et al. (2012, December) |
Namibia | |
| Ettler et al. (2009) |
Poland | |
| Puziewicz et al. (2007) +1 other reference |
USA | |
| Verbeek |
| Piatak et al. (2010) |
| Palache (1935) +1 other reference |
King (n.d.) | |
Christopher O'Neill | |
King (n.d.) +1 other reference | |
Weissman purchased specimen |
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Franklin Mine, Franklin, Sussex County, New Jersey, USA