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About HardystoniteHide

light brownish white, pale greyish-white, whitish, very pale pinkish
Adamantine, Resinous, Dull
3 - 4
Crystal System:
Member of:
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 for gemological information about Hardystonite.

Classification of HardystoniteHide

Approved, 'Grandfathered' (first described prior to 1959)

9 : SILICATES (Germanates)
B : Sorosilicates
B : Si2O7 groups, without non-tetrahedral anions; cations in tetrahedral [4] and greater 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 : Silicates not Containing Aluminum
7 : Silicates of Ba, Sr and Zn

Physical Properties of HardystoniteHide

Adamantine, Resinous, Dull
light brownish white, pale greyish-white, whitish, very pale pinkish
3 - 4 on Mohs scale

Optical Data of HardystoniteHide

Uniaxial (-)
RI values:
nω = 1.672 nε = 1.661
Max Birefringence:
δ = 0.011
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:

Chemical Properties of HardystoniteHide

IMA Formula:
Common Impurities:

Crystallography of HardystoniteHide

Crystal System:
Class (H-M):
4 2m - Scalenohedral
Space Group:
P4 21m
Cell Parameters:
a = 7.8287(16) Å, c = 5.0140(2) Å
a:c = 1 : 0.64
Unit Cell V:
307.30 ų (Calculated from Unit Cell)
Large, rough crystals rare embedded in calcite or other matrix.

X-Ray Powder DiffractionHide

Image Loading

Radiation - Copper Kα
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Type Occurrence of HardystoniteHide

Geological Setting of Type Material:
Occurs in a metamorphosed zinc-manganese-iron silicate-oxide orebody.

Other Language Names for HardystoniteHide

Simplified Chinese:锌黄长石

Relationship of Hardystonite to other SpeciesHide

Member of:
Other Members of this group:
ÅkermaniteCa2Mg(Si2O7)Tet. 4 2m : P4 21m
Alumoåkermanite(Ca,Na)2(Al,Mg,Fe2+)(Si2O7)Tet. 4 2m : P4 21m
GehleniteCa2Al(AlSiO7)Tet. 4 2m : P4 21m
Hydroxylgugiaite(Ca,□)2(Si,Be)(Be,Si)2O5(OH)2Tet. 4 2m : P4 21m

Common AssociatesHide

Associated Minerals Based on Photo Data:
Willemite160 photos of Hardystonite associated with Willemite on
Franklinite106 photos of Hardystonite associated with Franklinite on
Calcite86 photos of Hardystonite associated with Calcite on
Clinohedrite79 photos of Hardystonite associated with Clinohedrite on
Esperite24 photos of Hardystonite associated with Esperite on
Andradite22 photos of Hardystonite associated with Andradite on
Bustamite16 photos of Hardystonite associated with Bustamite on
Zincite9 photos of Hardystonite associated with Zincite on
Diopside8 photos of Hardystonite associated with Diopside on
Rhodonite7 photos of Hardystonite associated with Rhodonite on

Related Minerals - Nickel-Strunz GroupingHide

9.BB.10ÅkermaniteCa2Mg(Si2O7)Tet. 4 2m : P4 21m
9.BB.10GehleniteCa2Al(AlSiO7)Tet. 4 2m : P4 21m
9.BB.10Alumoåkermanite(Ca,Na)2(Al,Mg,Fe2+)(Si2O7)Tet. 4 2m : P4 21m
9.BB.15Barylite-1OBe2Ba(Si2O7)Mon. m : Pm

Related Minerals - Dana Grouping (8th Ed.)Hide,Na)2(Be,Al)(Si2O7,HSi2O7)Orth. 2 2 2 : P21 21 21,Na)2(Be,Al)[Si2O6(OH,F)]Tet. 4 : I4

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

14.7.2KrauskopfiteBaSi2O5 · 3H2OMon.
14.7.4MacdonalditeBaCa4Si16O36(OH)2 · 10H2OOrth.
14.7.5EricssoniteBaMn2+2Fe3+(Si2O7)O(OH)Mon. 2/m : B2/m
14.7.11WillemiteZn2SiO4Trig. 3 : R3
14.7.12HemimorphiteZn4Si2O7(OH)2 · H2OOrth. mm2 : Imm2
14.7.13ZincsiliteZn3(Si4O10)(OH)2 · 4H2OMon.
14.7.16ClinohedriteCaZn(SiO4) · H2OMon. m : Bb
14.7.17JunitoiteCaZn2Si2O7 · H2OOrth. mm2
14.7.18LarsenitePbZnSiO4Orth. mm2 : Pna21
14.7.19EsperitePbCa2Zn3(SiO4)3Mon. 2/m : P21/b
14.7.22GageiteMn21(Si4O12)2O3(OH)20Mon. 2/m
14.7.23FranklinfurnaceiteCa2Fe3+Mn2+3Mn3+(Zn2Si2O10)(OH)8Mon. 2 : B2

Fluorescence of HardystoniteHide

Dull persistent purple to blue (SW UV); blue (LW UV).

Other InformationHide

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.

References for HardystoniteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Wolff J E (1899) On hardystonite, a new calcium-zinc silicate from Franklin Furnace, New Jersey. Proceedings of the American Academy of Arts and Sciences 34, 479-481
Palache, C. (1935), USGS PP 180: 94.
Dunn, Pete J. (1995): Pt3: 411-412.
Zeitschrift für Kristallographie: 130: 427-437.

Internet Links for HardystoniteHide

Localities for HardystoniteHide

This 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.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for 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 (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
Czech Republic
  • 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.
  • North Rhine-Westphalia
    • Sauerland
      • Iserlohn
        • Letmathe
Bender, D. and Krimmelbein, W. (1994) Aktuelle Übersicht: Mineralien der Zinkhütte Genna/Sauerland. Stand Juni 1994. Mineralien-Welt, 4/94, 10.
  • Saxony-Anhalt
    • Mansfeld Basin
      • Hettstedt
Elmar Lackner collection
Besteman, Andre, et al, Hettstedt-smelter slag-dumps, Mansfeld Basin, Sachsen-Anhalt, Germany, The Strahlen Foundation.
  • Chihuahua
    • Mun. de Chihuahua
      • Avalos
Espejel-Garcia, D., Wenglas-Lara, G., Villalobos-Aragon, A., & Espejel-Garcia, V. V. (2012, December). Geochemical characterization and leaching behavior of slags: by-product materials from an old lead smelter in Chihuahua, Mexico. In AGU Fall Meeting Abstracts.
  • Oshikoto Region (Otjikoto Region)
    • 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.
  • 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.; Tyszka, R., Pietranik, A., Kierczak, J., Zieliński, G., & Darling, J. (2018). Cadmium distribution in Pb-Zn slags from Upper Silesia, Poland: Implications for cadmium mobility from slag phases to the environment. Journal of Geochemical Exploration, 186, 215-224.
  • California
    • San Bernardino Co.
      • San Bernardino Mts
        • Bear Valley District
          • Fawnskin (Grout)
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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