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Hardystonite

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Formula:
Ca
 
2
Zn(Si
 
2
O
 
7
)
System:TetragonalColour:light brownish white, ...
Hardness:3 - 4
Member of:Melilite Group
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.


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. Currently in public beta-test.

Classification of Hardystonite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:8/C.02-40
Nickel-Strunz 10th (pending) edition ID:9.BB.10

9 : SILICATES (Germanates)
B : Sorosilicates
B : Si2O7 groups, without non-tetrahedral anions; cations in tetrahedral [4] and greater coordination
Dana 8th edition ID: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
Hey's CIM Ref.:14.7.14

14 : Silicates not Containing Aluminum
7 : Silicates of Ba, Sr and Zn
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Type Occurrence of Hardystonite

Type Locality:Franklin Mine, Franklin, Franklin Mining District, Sussex Co., New Jersey, USA
Year of Discovery:1899
Geological Setting of type material:Occurs in a metamorphosed zinc-manganese-iron silicate-oxide orebody.

Physical Properties of Hardystonite

Lustre:Adamantine, Resinous, Dull
Diaphaneity (Transparency):Opaque
Colour:light brownish white, pale greyish-white, whitish, very pale pinkish
Streak:white
Hardness (Mohs):3 - 4
Cleavage:Distinct/Good

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 Volume:V 307.30 ų (Calculated from Unit Cell)
Z:2
Morphology:Large, rough crystals rare embedded in calcite or other matrix.
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Optical Data of Hardystonite

Type:Uniaxial (-)
RI values: nω = 1.672 nε = 1.661
Maximum Birefringence:δ = 0.011

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate

Chemical Properties of Hardystonite

Formula:
Ca
 
2
Zn(Si
 
2
O
 
7
)
Simplified for copy/paste:Ca2Zn(Si2O7)
Essential elements:Ca, O, Si, Zn
All elements listed in formula:Ca, O, Si, Zn
Analytical Data:Often replaced by, or being replaced by esperite. The latter condition very apparent under UV light as whisps and veils of esperite invading the hardystonite.
Common Impurities:Al,Fe,Mn,Pb,Mg,Na

Relationship of Hardystonite to other Species

Member of:Melilite Group
Other Members of Group:

- +
Åkermanite
Ca
 
2
Mg(Si
 
2
O
 
7
)
Alumoåkermanite
(Ca,Na)
 
2
(Al,Mg,Fe
2+
 
)(Si
 
2
O
 
7
)
Ferri-gehlenite
Ca
 
2
Fe
3+
 
AlSiO
 
7
Gehlenite
Ca
 
2
Al(AlSiO
 
7
)
Gugiaite
Ca
 
2
Be(Si
 
2
O
 
7
)
Okayamalite
Ca
 
2
B(BSiO
 
7
)
Related Minerals - Nickel-Strunz Grouping):

- +
9.BB.10Åkermanite
Ca
 
2
Mg(Si
 
2
O
 
7
)
9.BB.10Cebollite
Ca
 
5
Al
 
2
(SiO
 
4
)
 
3
(OH)
 
4
9.BB.10Gehlenite
Ca
 
2
Al(AlSiO
 
7
)
9.BB.10Gugiaite
Ca
 
2
Be(Si
 
2
O
 
7
)
9.BB.10Jeffreyite
(Ca,Na)
 
2
(Be,Al)(Si
 
2
O
 
7
,HSi
 
2
O
 
7
)
9.BB.10Okayamalite
Ca
 
2
B(BSiO
 
7
)
9.BB.10Alumoåkermanite
(Ca,Na)
 
2
(Al,Mg,Fe
2+
 
)(Si
 
2
O
 
7
)
9.BB.15Barylite
Be
 
2
Ba(Si
 
2
O
 
7
)
9.BB.15Barylite-1O
Be
 
2
Ba(Si
 
2
O
 
7
)
9.BB.20Andrémeyerite
BaFe
2+
2
(Si
 
2
O
 
7
)
Related Minerals - Hey's Index Grouping:

- +
14.7.1Sanbornite
Ba
 
2
(Si
 
4
O
 
10
)
14.7.2Krauskopfite
BaSi
 
2
O
 
5
· 3H
 
2
O
14.7.3Walstromite
BaCa
 
2
(Si
 
3
O
 
9
)
14.7.4Macdonaldite
BaCa
 
4
Si
 
16
O
 
36
(OH)
 
2
· 10H
 
2
O
14.7.5Ericssonite
BaMn
2+
2
Fe
3+
 
(Si
 
2
O
 
7
)O(OH)
14.7.6Ericssonite-2O
BaMn
2+
2
Fe
3+
 
(Si
 
2
O
 
7
)O(OH)
14.7.7Gillespite
BaFe
2+
 
[Si
 
4
O
 
10
]
14.7.8Andrémeyerite
BaFe
2+
2
(Si
 
2
O
 
7
)
14.7.9Pellyite
Ba
 
2
Ca(Fe,Mg)
 
2
Si
 
6
O
 
17
14.7.10Taikanite
Sr
 
3
BaMn
2+
2
(Si
 
4
O
 
12
)O
 
2
14.7.11Willemite
Zn
 
2
SiO
 
4
14.7.12Hemimorphite
Zn
 
4
Si
 
2
O
 
7
(OH)
 
2
· H
 
2
O
14.7.13Zincsilite
Zn
 
3
(Si
 
4
O
 
10
)(OH)
 
2
· 4H
 
2
O
14.7.15Petedunnite
Ca(Zn,Mn
2+
 
,Mg,Fe
2+
 
)Si
 
2
O
 
6
14.7.16Clinohedrite
CaZn(SiO
 
4
) · H
 
2
O
14.7.17Junitoite
CaZn
 
2
Si
 
2
O
 
7
· H
 
2
O
14.7.18Larsenite
PbZnSiO
 
4
14.7.19Esperite
PbCa
 
2
Zn
 
3
(SiO
 
4
)
 
3
14.7.20Hodgkinsonite
Mn
2+
 
Zn
 
2
(SiO
 
4
)(OH)
 
2
14.7.21Gerstmannite
MnMgZn(SiO
 
4
)(OH)
 
2
14.7.22Gageite
Mn
 
21
(Si
 
4
O
 
12
)
 
2
O
 
3
(OH)
 
20
14.7.23Franklinfurnaceite
Ca
 
2
Fe
3+
 
Mn
2+
3
Mn
3+
 
(Zn
 
2
Si
 
2
O
 
10
)(OH)
 
8

Other Names for Hardystonite

Other Languages:
German:Hardystonit
Russian:Гардистонит
Simplified Chinese:锌黄长石
Spanish:Hardystonita

Other Information

Fluorescence in UV light:Dull persistent purple to blue (SW UV); blue (LW UV).
Health Warning: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

References for Hardystonite

Reference List:

- +
Palache, C. (1935), USGS PP 180: 94.

Dunn, Pete J. (1995): Pt3: 411-412.

Zeitschrift für Kristallographie: 130: 427-437.

Internet Links for Hardystonite

Search Engines:
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  • External Links:
  • Look for Hardystonite on Webmineral
  • Look for Hardystonite on Athena Mineralogy
  • Look for Hardystonite on Wikipedia
  • Look for Hardystonite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Hardystonite details from Handbook of Mineralogy (PDF)
  • Mineral Dealers:
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  • SpiriferMinerals.com - high quality low prices
  • Buy from McDougall Minerals
  • Find Hardystonite on www.crystalclassics.co.uk
  • Buy fine minerals and gemstones from Pala International
  • Fine and rare minerals from mintreasure.com
  • Rare and Unusual minerals at Mineralogical Research Company
  • Top quality minerals from Kristalle of California
  • Buy from David K Joyce minerals
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  • Hardystonite specimens for sale - minfind.com
  • Buy rare minerals from Excalibur Minerals
  • Localities for Hardystonite

    The 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.
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Czech Republic
     
    • Bohemia (Böhmen; Boehmen)
      • Central Bohemia Region
        • Kutná Hora (Kuttenberg)
          • Poličany
            • Vrchlice river valley
    Pauliš P. Mineralogické lokality okolí Kutné Hory. Kuttna, Kutná Hora 1999. ISBN 80-902719-0-1.
    Germany
     
    • Saxony-Anhalt
      • Mansfeld Basin
        • Hettstedt
    Elmar Lackner collection
    Besteman, Andre, et al, Hettstedt-smelter slag-dumps, Mansfeld Basin, Sachsen-Anhalt, Germany, The Strahlen Foundation.
    Namibia
     
    • Otjikoto Region (Oshikoto)
      • Tsumeb
    Ettler, V., Johan, Z., Kříbek, B., Šebek, O. & Mihaljevič, M. (2009): Mineralogy and environmental stability of slags from the Tsumeb smelter, Namibia. Applied Geochemistry 24, 1-15.
    Poland
     
    • Upper Silesia (Śląskie)
      • Katowice
        • Świętochłowice
    Puziewicz, J., Zainoun, K. and Bril, H. (2007): Primary phases in pyrometallurgical slags from a zinc-smelting waste dump, Świętochłowice, Upper Silesia, Poland. Can. Mineral. 45, 1189-1200.
    USA
     
    • California
      • San Bernardino Co.
        • Bear Valley Mining District
    Verbeek, Earl R. and Van Fleet, James, 2014, Hardystonite from the Desert View Mine, California: The Picking Table, vol. 55, no. 1, p. 15-17.
    • Illinois
      • Vermilion Co.
        • Danville
          • Hegeler
    Piatak, N. M. & Seal, R. R., II (2010): Mineralogy and the release of trace elements from slag from the Hegeler Zinc smelter, Illinois (USA). Applied Geochemistry, 25, 302-320
    • New Jersey
      • Sussex Co.
        • Franklin Mining District
          • Franklin
    Palache(1935):94; Dunn(1995):Pt3:411-412.
    Van King
    Christopher O'Neill
    Van King; Chester S. Lemanski, Jr.
    Weissman purchased specimen
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