Fluorescent Minerals

Fluorescence is a phenomenon in some minerals where they emit visible light when exposed to radiation that is not normally visible, in this case ultraviolet (UV) radiation. When exposed to UV radiation, some rocks that may look rather ordinary under normal light will glow in a display of vibrant colours associated with the minerals present. Common minerals known to fluoresce include fluorite and calcite. Take a look at some common and not so common minerals below!

Acknowledgements

The display poster was created by student volunteer Ezra Hovi with feedback from Dr. Alysha McNeil and Dr. Brendt Hyde. The display was set-up by Dr. Brendt Hyde and Olivia Benest. Photos for this webpage were taken by Olivia Benest.

Dana Collection - Opal

753_Opal_Dana_Split_415.jpg

Dana Collection Sample Number 753 – Opal

Virgin Valley, Humbolt Co., Nevada

Chemical Formula: SiO2•n(H2O)

This sample of opal from Virgin Valley, Nevada fluoresces in brilliant blues and greens under UV. Although it is considered a valid mineral species, opal is actually amorphous SiO2 with a variable amount of water.

Dana Collection - Scapolite

868_Scapolite_Dana_Split_415.jpg

Dana Collection Sample Number 868 – Scapolite

Grenville Township, Quebec

Chemical Formula: (Na,Ca)4(Al3Si9O24)Cl

The term scapolite actually refers to a group of aluminosilicate minerals. Scapolite often strongly fluoresces yellow, which is the case here and for the other scapolite samples in this display.

Dana Collection - Franklinite with Calcite and Willemite

2384_Franklinite_Dana_Split_415.jpg

Dana Collection Sample Number 2384 – Franklinite

Franklin, New Jersey

Chemical Formula: (Zn,Mn,Fe)(Fe,Mn)2O4

This zinc ore mineral from Franklin, New Jersey actually doesn’t fluoresce, but a number of minerals from this locality do! The black franklinite in this sample is accented by willemite (green under UV) and calcite (pinkish under UV in this sample).

Dana Collection - Sodalite

8801_Hackmanite_Sodalite_Split_415.jpg

Dana Collection Sample Number 8801 – Sodalite

Quebec

Chemical Formula: Na8Al6Si6O24Cl2

Sodalite is named for its composition, which includes sodium. The sample in this display is a variety of sodalite called hackmanite. Long wavelength UV light sets-off an orange fluorescence from this mineral.

Dana Collection - Adamite

2832_Adamite_Dana_Split_415.jpg

Dana Collection Sample Number 2832 – Adamite

Mina Ojuela, Mapimi, Durango, Mexico

Chemical Formula: Zn2(AsO4)(OH)

Adamite is a zinc arsenate hydroxide mineral that fluoresces yellow-green under UV. This mineral’s eye-catching crystals and distinctive fluorescence make it a favourite of mineral collectors.

Dana Collection - Sphalerite

2829_Sphalerite_Dana_Split_415.jpg

Dana Collection Sample Number 2829 – Sphalerite

Junction Shaft, Bisbee, Cochise Co., Arizona

Chemical Formula: (Zn,Fe)S

Sphalerite is the most common zinc ore and fluoresces in a wide range of colours under UV. In this case, a brilliant yellow-orange. Sphalerite can also be triboluminescent meaning light is generated when it is mechanically pulled apart, scratched and crushed!

Dana Collection - Scapolite

2632_Scapolite_Dana_Split_415.jpg

Dana Collection Sample Number 2632 – Scapolite

Unknown locality

Chemical Formula: (Na,Ca)4(Al3Si9O24)Cl

The term scapolite actually refers to a group of aluminosilicate minerals. Scapolite often strongly fluoresces yellow, which is the case here and for the other scapolite samples in this display.

Dana Collection - Fluorite

8802_Fluorite_Dana_Split_415.jpg

Dana Collection Sample Number 8802 – Fluorite

Mexico

Chemical Formula: CaF2

The phenomenon of “fluorescence” actually derives its name from fluorite! This mineral commonly fluoresces blue. The sample on display here is green in natural light, but switches to fluorescing blue under UV.

Suffel Collection - Willemite

1008_Willemite_Suffel_Split_415.jpg

Suffel Collection Sample Number 1008 – Willemite

Franklin, New Jersey

Chemical Formula: Zn2SiO4

Willemite is a zinc silicate and can be found in association with the zinc ore mineral franklinite (there is a small amount here). Although this sample appears quite unassuming in natural light, it fluoresces bright green under UV.

Dana Collection - Willemite with Calcite

8799_Calcite_Willemite_Dana_Split_415.jpg

Dana Collection Sample Number 8799 – Willemite

New Jersey

Chemical Formula: Zn2SiO4

This sample is a mixture of two minerals seen elsewhere in the display. Here the zinc silicate willemite (fluorescing green under UV) is surrounded by calcite (fluorescing pink-purple under UV).

Dana Collection - Calcite

1361_Calcite_Dana_Split_415.jpg

Dana Collection Sample Number 1361 – Calcite

Cumberland, England

Chemical Formula: CaCO3

Probably the most common mineral to show fluorescence under UV, calcite is also unique in showing a large range of fluorescent colours. This fact, combined with the large number of interesting crystal habits seen in calcite, make it popular with fluorescent mineral collectors. The sample in this display fluoresces a vibrant pink.

Dana Collection - Scapolite

8800_Scapolite_Dana_Split_415.jpg

Dana Collection Sample Number 8800 – Scapolite

Quebec

Chemical Formula: (Na,Ca)4(Al3Si9O24)Cl

The term scapolite actually refers to a group of aluminosilicate minerals. Scapolite often strongly fluoresces yellow, which is the case here and for the other scapolite samples in this display.