Posted On: Sunday, March 8, 2015
The geology community knows a lot about mineral fluorescence under excitation by various wavelengths of ultraviolet light but when it comes to excitation by light in the visible portion of the spectrum, such as blue, … not so much. In December 2013 Charles Mazel (NIGHTSEA) and Earl Verbeek (Sterling Hill Mining Museum) explored the extensive collection of the Franklin Mineral Museum (Franklin, New Jersey, USA) for instances of blue-light-stimulated fluorescence. When fluorescence occurred the specimen was photographed under white light, fluorescing under blue light, and fluorescing under either or both of shortwave and longwave ultraviolet light. The results were published in September 2014 – Mazel, C.H. and Verbeek, E.R. (2014), Fluorescence of minerals under blue light. The Picking Table (Journal of the Franklin-Ogdensburg Mineralogical Society), vol. 55, no. 2, p. 13-25.
We will share the photographic results in a series of blog posts, each documenting one specimen. See the summary of all posts to date.
The editors of The Picking Table have graciously allowed us to make the fall 2014 issue with our article on blue light mineral fluorescence available for free download. Click the image of the cover to access the pdf. And we certainly encourage you to join FOMS so that you can keep up with their activities and receive future issues.
Mineral (primary) – Fluorapatite
Specimen identifier – FMM 7364
Approximate size (cm) – 11 x 8.5 x 4
White light – Greenish gray is fluorapatite, black franklinite, brown andradite, pale gray to white spots are calcite
Blue light – fluorescence: mottled greenish-yellow is fluorapatite; orange patches (largest, lower left) are calcite
Shortwave ultraviolet – fluorescence: orange/brown is fluorapatite; bright orange spots/patches are calcite; tiny green dots at lower right are willemite dust, not part of the specimen
Longwave ultraviolet – fluorescence: fluorapatite is non-fluorescent (no picture taken)
(Click on image for larger view)