Fluorite
Halides
CaF₂

The common blue fluorescence seen in fluorites, which is responsible for the naming of the phenomenon of fluorescence itself in the year 1852 by George Gabriel Stokes, has been attributed to the presence of inclusions of europium in the crystal.





Calcite (Mangano-calcite)
Carbonates
(Ca,Mn)CO₃
New South Wales, Australia

Some minerals which do not normally fluoresce will sometimes do so because of an activator. For instance, most forms of calcite do not fluoresce. Yet, if a small amount of manganese is present in the mineral, it acts as an activator and causes the calcite to fluoresce red. The brilliance of the fluorescence varies with the amount of manganese.




Autunite
Phosphates
Ca(UO₂)₂(PO₄)₂·10-12H₂O
USA

In autunite, the activator element Uranium, in the form of the uranyl cation, causes a yellow-green fluorescence. Unlike manganese, the uranyl ion in minerals is quite insensitive to its atomic environment, and thus a similar color of fluorescence appears regardless of the mineral species.

Opal
Tectosilicates
SiO₂·nH₂O
Nevada, USA

Opal (var. Hyalite)
Tectosilicates
SiO₂·nH₂O
North Carolina, USA

Opal and Hyalite, a form of opal with a glassy and clear appearance, show a bright-green fluorescence due to the presence of Uranium as an activator.

Calcite with Willemite and Franklinite
CaCO₃, Zn₂SiO₄, ZnFe₂O₄
New Jersey, USA

Willemite with Calcite and Franklinite
Zn₂SiO₄, CaCO₃, ZnFe₂O₄
New Jersey, USA

This is a classic combination of Calcite, Willemite and Franklinite from a Zinc and Manganese Ore Deposit at Sterling Hills in New Jersey (USA) renowned for its bright fluorescence colors in some minerals due to the presence of Manganese as an activator. The tan-colored Willemite exhibits a bright green fluorescence while the white-colored calcite exhibits a pink fluorescence. The iron-rich mineral Franklinite is not fluorescent and is represented by the dark areas in the photo.

Scapolite
Tectosilicates
(Na,Ca)₄Al₃Si₉O₂₄Cl
Québec, Canada

Scapolite from Quebec in Canada fluoresces a vivid orangeish-yellow color, probably activated by sulfur or uranium impurities.