Database of luminescent Minerals

DOLOMITE

Chemical Formula: CaMg(CO₃)₂

Familly: Carbonates

Status: IMA-GP

Crystal System: Rhomboedric

Mineral for Display: Yes

Luminescence:

Daylight Picture

DOLOMITE,
Horn Silver Mine, Beaver County, Utah, USA;
Photo and Copyright: James Horste
Used with permission of the author.

Short Waves Pictures (254nm)

DOLOMITE,UVSW
Horn Silver Mine, Beaver County, Utah, USA;
Photo and Copyright: James Horste
Used with permission of the author.

Galerie de photos:

     To the gallery (2 images in the gallery)

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

Triboluminescence: Yes

Thermoluminescence: Yes

Comments:

The Crazy Calcite fluo red SW from Franklin, USA is sometime composed by dark red SW fluorescing Dolomite mixed with bright red SW fluorescing Calcite, with black Franklinite  and tiny yellow Diopside crystals. The LW response is in shades of red-pink. It is however possible that the fluorescence of dolomite is due to the observation of the phenomenal fluorescence of calcite by transparency. 

Main Activator(s) and spectrum:

Most Common Activator: Mn²⁺

Other activators:            Organic impurities , Ce³⁺ , Sm³⁺ , Dy³⁺ , Tb³⁺ , Gd³⁺ ,

Peaks in the spectrum (nm):

Mn²⁺I repl. Ca²⁺ : 578 - 582nm
Mn²⁺II repl. Mg²⁺ : 650 -  660nm
Ce³⁺: 360 - 370nm 
Gd³⁺ : 312 nm
Tb³⁺ : 480, 545nm
Dy³⁺  : 478, 500, 572, 585nm
Eu³⁺ : 610 nm
Sm³⁺ : 560, 602, 645nm
[CO]_n^*? intr. :  410nm 
ST: 475nm
530 (?)

Comments on activators and spectra:

The following emission centers have been found by steady-state spectroscopy:

two different Mn2+ centers substituting for Ca2+ and Mg2+ and rare-earth elements such as Ce3+, Gd3+, Tb3+, Dy3+ and Sm3+ substituting for Ca2+ (Gorobets and Rogojine).

Cathodoluminescence:

Deconvolution of corrected CL spectra from dolomite shows two overlapping peaks at 17315 cm⁻¹ (578 nm) and 15270 cm⁻¹ (655 nm).

In rare cases only the 655 nm Gaussian peak is present.

The CL peak at 578nm (I_a) is due to Mn²⁺ in the Ca site and the peak at 655nm (I_b) to Mn²⁺ in the Mg position.

The Mn²⁺ content in dolomite is linearly correlated with the normalized EPR areas of the two sites.

The distribution ratio (KD) of Mn²⁺ in the two sites of dolomite, i.e. the Ca and the Mg position, was determined by EPR and CL spectroscopy. A linear correlation exists between KD from EPR and the intensity ratio I_bI_a from CL. CL spectroscopy is thus an appropriate method to determine KD in dolomite and evaporitic dolomites may be differentiated from non-evaporitic dolomites by their KD-values. (see: Mn²⁺-activated luminescence in dolomite, calcite and magnesite: quantitative determination of manganese and site distribution by EPR and CL spectroscopy, Ahmad El Ali et Al., Chemical Geology, Volume 104, Issues 1–4, 10 February 1993, Pages 189-202)

Best Locality for luminescence(*):

• Horn Silver Mine, Beaver County, Utah, USA;
• Langban, Varmland Province, Sweden (red SW);
• San Bernardo Quarry, Zandobbio, Bergamo Province, Lombardy, Italy (pink);
• Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia (fluo orange);

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

Bibliographical Reference for luminescence:

• The Henkel Glossary of Fluorescent Minerals, Dr. Gerhard Henkel, Published by the FMS, 1989 ,
• Luminescent Spectra of Minerals, Boris S. Gorobets and Alexandre A. Rogojine, Moscow, 2002 ,

Luminescence Reference on internet:

• Mn-activated luminescence in dolomite, calcite and magnesite: quantitative determination of manganese and site distribution by EPR and CL spectroscopy, Ahmad El Ali, Vincent Barbin, Georges Calas, Bernard Cervelle, Karl Ramseyer, Jacqueline Bouroulec, Chemical Geology, Volume 104, Issues 1–4, 10 February 1993, Pages 189–202

 

Images:

 

• Arraia-Maeztu, Álava, Basque Country, Spain: https://www.mindat.org/photo-556003.html
• Franklin, USA: https://www.mindat.org/photo-629957.html

Mineralogical Reference on internet:

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

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

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