Database of luminescent Minerals


Chemical Formula: Ca2ZnSi2O7

Familly: Silicates

Status: IMA-GP

Crystal System: Tetragonal

Mineral for Display: Yes


UV Type Main color Intensity Observation Frequency
Long Waves (365nm):      Violet blue WeakRarely
Mid waves (320 nm):      Violet blue MediumOften
Short Waves (254 nm):      Violet blue MediumVery often
Other colors SW:          
Blue , Violet ,

Daylight Picture

HARDYSTONITE with minor Willemite,
Franklin, New Jersey zinc mine, USA;
Photo and Copyright: James Van Fleet

Short Waves Pictures (254nm)

HARDYSTONITE (UVSW) with minor Willemite (fluo green)
and some Clinohedrite (fluo orange)
Franklin, New Jersey zinc mine, USA;
Photo and Copyright: James Van Fleet


Phosphorescence (in the common meaning of the term) seen by naked eye:

No Data


A classics for Franklin minerals collectors.

Some samples appear to fluoresce brighter under MW than SW; this phenomenon could be due to the fact that the response of the willemite often associated is duller under MW, so the fluorescence of hardystonite is better viewed. 


Main Activator(s) and spectrum:

Most Common Activator: Mn2+

Other activators:            Pb2+ , Ce3+ , Dy3+ , Gd3+ , Tm3+ ,

Peaks in the spectrum (nm):

Pb2+: 355nm
Ce3+: 378nm
Ce3+: 400nm
Mn2+: 525nm
Mn2+: 545nm
Mn2+: 575nm
Gd3+ : 312nm
Dy3+ : 480, 575nm
Tm3+ : 452nm

Spectrum: Michael Gaft, Petah Tikva, Israel. Plot: Institute of Mineralogy, University of Vienna, Austria, with permission of the authors.


  To the spectrum gallery (2 spectra in the gallery)

Comments on activators and spectra:

Pb2+  : 355 nm 
Mn2+ :  525 and 575nm
Ce3+ : 378, 400 nm
Tm3+, Dy3+

Decay time: several ms

Best Locality for luminescence(*):

(*)Data are not exhaustive and are limited to the most important localities for fluorescence

Bibliographical Reference for luminescence:

Luminescence Reference on internet:

Mineralogical Reference on internet:

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Note: While all due attention has been paid to the implementation of the database, it may contain errors and/or accidental omissions. By nature, the database will always be incomplete because science always evolves according to new analysis.
A request providing no result means only that no such reference exists in the database, but it does not mean that what you are looking for does not exist, just not to our knowledge. If you think you have found an error or omission, please let us know via the contact page being sure to cite the source of information.


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