2. Fluorescent Minerals
What is a Fluorescent Mineral?
These minerals have the ability to temporarily
absorb a small amount of light and an instant later
release a small amount of light of a different
wavelength. This change in wavelength causes a
temporary color change of the mineral in the eye of
a human observer.
4. Fluorescent Minerals
WHAT IS ULTRAVIOLET (UV)?
Fluorescence is a "cold light" (luminescence) caused by
electromagnetic radiation. There are many forms of
electromagnetic radiation: visible light, radio, infrared, ultraviolet,
X-rays, and gamma rays are all forms of electromagnetic
radiation.
5. Fluorescent Minerals
Ultraviolet radiation, as generated by a "black light" or Ultra
Violet lights, is that portion of the electromagnetic spectrum
that lies beyond the purple edge of the visible spectrum and
has wavelengths between 100 and 400 nm.
WHAT IS ULTRAVIOLET (UV)?
6. Fluorescent Minerals
For the fluorescent mineral collector there are three useful
wavelengths of ultraviolet light; Long wave, Mid wave, and
Short wave. A few minerals fluoresce the same color in all
wavelengths, others fluoresce in only one wavelength (usually
SW), and yet others fluoresce different colors in different
wavelengths.
WHAT IS ULTRAVIOLET (UV)?
7. Fluorescent Minerals
Fluorite: The Original "Fluorescent Mineral”
One of the first people to observe fluorescence in minerals was
George Gabriel Stokes in 1852. He noted the ability of fluorite to
produce a blue glow when illuminated with invisible light "beyond
the violet end of the spectrum." He called this phenomenon
"fluorescence" after the mineral fluorite. The name has gained
wide acceptance in mineralogy, gemology, biology, optics,
commercial lighting and many other fields.
8. Fluorescent Minerals
FLUORESCENCE IN MINERALS
There are around 4,000 different types of minerals -
approximately 15% of them are known to
fluoresce. Impurities in the mineral (usually) cause
this fluorescence - very few "pure" minerals are
known to fluoresce.
9. Fluorescent Minerals
Fluorescence usually occurs when specific
impurities known as "activators" are
present within the mineral. These
activators are typically cations of metals
such as: tungsten, molybdenum, lead,
boron, titanium, manganese, uranium, and
chromium. Rare earth elements such as
europium, terbium, dysprosium, and
yttrium are also known to contribute to the
fluorescence phenomenon. Fluorescence
can also be caused by crystal structural
defects or organic impurities.
Fluorescence “Activators
10. Fluorescent Minerals
In addition to "activator" impurities, some
impurities have a dampening effect on
fluorescence. If iron or copper are present
as impurities, they can reduce or eliminate
fluorescence. Furthermore, if the activator
mineral is present in large amounts, that
can reduce the fluorescence effect
Fluorescence “Dampeners”
26. Fluorescent Minerals
Fluorescent Mineral References
[1] Basic Concepts in Fluorescence: Michael W. Davidson and
others, Optical Microscopy Primer, Florida State University, last
accessed October 2016.
[2] Fluorescent Minerals: James O. Hamblen, a website about
fluorescent minerals, Georgia Tech, 2003.
[3] The World of Fluorescent Minerals, Stuart Schneider, Schiffer
Publishing Ltd., 2006.
[4] Dugway Geodes page on the SpiritRock Shop website, last
accessed May 2017.
[5] Collecting Fluorescent Minerals, Stuart Schneider, Schiffer
Publishing Ltd., 2004.
[6] Ultraviolet Light Safety: Connecticut High School Science
Safety, Connecticut State Department of Education, last accessed
October 2016.
[7] A Contribution to Understanding the Effect of Blue
Fluorescence on the Appearance of Diamonds: Thomas M.
Moses and others, Gems and Gemology, Gemological Institute of
America, Winter 1997.
Good Reference Books
