Database of luminescent minerals 

BARYTE

Chemical formula: BaSO₄

Family: Sulfates

Status: IMA-GP

Crystal system : Orthorhombic

Display mineral: OUI

Associated names (luminescent varieties, discredited names, synonyms, etc.): barytine,  hokutolite,  Lepastrum, 

Luminescence:

Shortwave (254nm) picture

Baryte (fluo cream) in calcite (fluo red) SW,
Franklin Mine, Sussex Co., New Jersey, USA
Col. G. Barmarin; Photo: G. Barmarin

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Phosphorescence (in the common sense of the term) observable with the naked eye:

Comments:

Mineral barite is one of the first luminescent materials from which the famous Bologna stone was obtained.

Nevertheless, up today the understanding of natural barite luminescence is very scarce.

It has been known for a long time that some specimens of barite are fluorescent under UV exposure and emit white, yellow, green or orange light.

In steady-state luminescence spectra of barite different luminescence bands from the UV to the red part of the spectrum have been detected.

However, only UO₂²⁺ and Eu²⁺ luminescence centers have been confidently identified (Tarashchan 1978; Gaft et al. 1985).

Laser-induced time-resolved technique enables to detect Ag⁺, Bi²⁺, Bi³⁺, Eu²⁺, Eu³⁺, Ce³⁺, Nd³⁺, (UO₂)²⁺ and several still not identified emission centers (Gaft et al. 2001, 2008b) 

Activator(s) and spectrum:

Activator(s): (UO₂)²⁺ (ion Uranyle) en impureté, Pb²⁺,   S₂^-,  ST (Singlet-triplet)-Matière organique en impureté,  Cu⁺,  Eu²⁺,  Ce³⁺,  Tb³⁺,  Ag⁺,  Nd³⁺,  Bi²⁺,  Bi³⁺,  

Peaks in the spectrum (nm):

Bi³⁺ : 426-430nm band 80nm half-width  ( τ = 750 microsecondes)

Bi²⁺ replacing Ba²⁺ : narrow band 625nm  ( τ = 5 microsecondes)

Ag⁺ : very broad band (150 nm half-width) peaking at 635nm  ( τ = 225 microsecondes)

Ce³⁺  : 302, 305, 330, 360nm 

Nd³⁺  : 389, 446, 589, 672nm  

Eu³⁺ : 592, 620, 701nm

Tb³⁺  : 488, 544nm  

UO₂²⁺  : 501, 522, 544, 568 

Eu²⁺  : 375, 613, 615, 697nm 

Pb      : blue part of the spectrum

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

Spectrum Galery:

  
  Go to the galery (3 spectra)

Comments on spectrum and activators:

It is known that the luminescent centers Eu²⁺ (1.24–1.40 Å), Ce³⁺ (0.88–1.02 Å), Nd³⁺ (0.99–1.15 Å), Tb³⁺ (0.89–1.09 Å), Ag⁺ (1.13–1.26 Å), Sn²⁺ (0.93 Å) substitute for Ba²⁺ (1.35–1.44 Å) or Sr²⁺ (1.10–1.27 Å), which are in 12-fold coordination in the barite structure (all ionic radii are for the 6-coordination form) (GOROBETS, 2002; GAFT et al., 2005);

A possible accommodation for the established in this study Eu³⁺ (0.97–1.13 Å) is also isomorphic substitution for Ba²⁺ or Sr²⁺

Ag⁺ (large pic 635 nm), Bi²⁺ in Ba²⁺ site (narrow band 625 nm), Bi³⁺ (426 nm), Eu²⁺ (375), Ce³⁺ (302, 330, 360nm), Nd³⁺ (446, 589nm) (Gaft)

Activators: (UO₂)²⁺

UO₂²⁺ can be determined from the vibrational structure and the long decay time of the luminescence band.

Two different types of uranyl could be detected in Baryte: thin films of uranyl mineral considered to be a result of chemical adsorption (GOROBETS, 2002) and a solid solution of uranyl ion in barite crystal.

Activators:  Eu²⁺

Eu²⁺ can be determined from the spectral position, the half-width and the characteristic decay time of the luminescence band.

Mn²⁺ and Ag⁺ can be determined by comparing luminescence bands spectral parameters to those of synthesized BaSO₄−Mn and BaSO₄−Ag.

Fe³⁺ or Mn⁴⁺ can be determined from the spectral-kinetic parameters of the luminescence bands.( After M. Gaft and I. Rudenkova, Laser-induced luminescence of barite after thermal treatment, Journal of Thermal Analysis and Calorimetry vol42, 1994)

In natural barite the narrow orange band with λmax=625 nm, Δ=40 nm and τ=5 μs is connected with Bi²⁺ center.
The narrow violet band with λmax=625 nm, Δ=35 nm and τ=1.7 ms is connected with Bi³⁺ center.
The broad red band with λmax=635 nm, Δ=140 nm and τ=270 μs is connected with Ag⁺ center. The emission bands of Ag+ result from d⁹s–d¹⁰ transitions
The broad red band with λmax=750 nm, Δ=110 nm and τ=350 μs is connected with Cu⁺ center.(The luminescence of Bi, Ag and Cu in natural and synthetic barite , M. Gaft, R. Reisfeldb, G. Panczer, G. Boulonc, T. Saraidarovb and S. Erlishd, Optical Materials, vol16, 2001)

The luminescence spectrum (excitation of 266 nm, without delay, broad gate of 9 ms) of the studied endogenous barite contains 2 relatively narrow ultraviolet bands: one peaking at 306 nm and the other at 375 nm. The first band has a very short decay time and disappears after D = 50–100 ns. Such a combination of spectrum and decay time parameters is evidence that the luminescence is connected with Ce³⁺. The emission of Ce³⁺ corresponds to transitions between 5d¹ and 4f¹ electronic configurations. The second band has a longer decay time of approximately 1 μs and belongs to Eu²⁺ (GAFT et al., 2005). The Emission spectra of Eu²⁺ result from electronic transitions between 4f⁷ and 4f⁶5d¹ electronic configurations. After a delay of several μs, the Eu²⁺ emission becomes much weaker and very weak narrow lines appear, peaking at 488, 544 and 615 nm ). These lines are connected with trivalent rare-earth elements, which are characterized by relatively long decay times of hundreds of μs: the first 2 lines certainly belong to Tb³⁺ and the last one is principally typical for Eu³⁺ (GAFT et al., 2005). While Eu²⁺ luminescence is common, Eu³⁺ emission is here detected for the first time in barite. Under the excitation of 532 nm, a luminescence line at 615 nm dominates the spectrum, accompanied by several lines near 700 nm. Such behavior confirms that Eu³⁺ is responsible for these luminescence lines. The emission of Eu³⁺ corresponds to f–f transitions – from the excited ⁵D₀ level to the ⁷F_j (j=0, 1, 2, 3, 4, 5, 6) levels of the 4f₆ configuration.
The different emission spectra at excitations at 266 and 532 nm suggest at least 2 structural positions for Eu³⁺ in the barite crystal lattice.

(Spectroscopic study of barite from the Kremikovtsi deposit (Bulgaria) with implication for its origin, MAYA DIMOVA, GERARD PANCZER & MICHAEL GAFT, ANNALES GÉOLOGIQUES DE LA PÉNINSULE BALKANIQUE, Vol67, 2006 See link below)

Best localities for fluorescence (*):

• Franklin Mine, Franklin, New Jersey, USA (Baryte fluo yellow in massive calcite fluo red SW);
• 700 Level, Sterling Hill Mine, Ogdensburg, New Jersey, USA (Baryte fluo yellow in massive calcite fluo red SW);
• Edison Tunnel, Sterling Hill Mine, Ogdensburg, New Jersey, USA (Baryte fl. yellow LW and sphalerite fl.orange LW within willemite fl. Green SW, franklinite  and massive calcite fl. red SW);
• Langban, Filipstad, Varmland, Sweden (fluo blue due to 1% Pb);
• Moscona Mine, Solís, Corvera de Asturias, Asturias, Spain (yellowish white LW)
• Book Cliffs area, Grand Junction, Mesa Co., Colorado, USA (white LW due to oil hydrocarbons + phosphor.);
• Silver Cliff Mining District, Custer Co., Colorado, USA (orange SW+MW+LW)
• Cerro Warihuyn (Huarihuyn), Miraflores, Huamalíes Province, Huánuco Department, Peru;
• Chengkou Co., Chongqing, China;

(*)The data are not exhaustive and are limited to a few remarkable localities for fluorescence

Bibliographic reference for luminescence:

• The Henkel Glossary of Fluorescent Minerals, Dr. Gerhard Henkel, Published by the FMS, 1989 ,
• Fluorescence: Gems and Minerals Under Ultraviolet Light, Manuel Robbins, 1994, Geoscience Press, ISBN 0-945005-13-X ,
• Luminescence Spectroscopy of Minerals and Materials, M. Gaft, R. Reisfeld, G. Panczer, Springer Editor, ISBN: 10 3-540-21918-8 ,
• Luminescent Spectra of Minerals, Boris S. Gorobets and Alexandre A. Rogojine, Moscow, 2002 ,
• Luminescenza nel regno minerale, Guido Mazzoleni, fotografia Roberto Appiani, Libri Sandit, 2010, ISBN 978-88-95990-63-7 ,

Reference for luminescence on the Internet:

Mineralogical reference on the Internet:

  http://www.mindat.org/show.php?name=Baryte

  http://webmineral.com/data/Baryte.shtml

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