Blue amber

Blue amber is amber exhibiting a rare coloration. It most commonly is found in the amber mines in the mountain ranges around Santiago, Dominican Republic. [cite web |url=http://ambarazul.com/wordpress/2006/09/ |title=Dominican Amber Mines: The Definitive List |accessdate=2008-04-15 |last=Corday|first=Alec|year=2006|work=The Blue Amber Blog|language=English] Although little known due to its rarity, it has been around since the discovery of Dominican amber. [Leif Brost and Ake Dahlstrom. The Amber Book, Geoscience Press, Inc., Tucson , AZ, 1996 ISBN 0-945005-23-7] [Manuel A. Iturralde-Vennet 2001. Geology of the Amber-Bearing Deposits of the Greater Antilles. Caribbean Journal of Science, Vol. 00, No. 0, 141-167, 2001] [Martínez, R. & Schlee, D. (1984): Die Dominikanischen Bernsteinminen der Nordkordillera, speziell auch aus der Sicht der Werkstaetten. – Stuttgarter Beitr. Naturk., C, 18: 79-84; Stuttgart.]

Causes of coloration

When natural light strikes Blue Amber on a white surface, the light particles pass right through, and then are refracted off the white surface. Result: the Blue Amber has a slight blue hue. When the same natural light particles strike the Amber on a black surface, the light particles don't refract off the black surface, thus refracting off the actual Amber. Hydrocarbons in the Blue Amber turn the sun's ultraviolet light into blue light particles, resulting in the glow of Blue Amber.

This effect is only possible in the Dominican Republic Blue Amber [Wilfred Wichard und Wolfgang Weitschat: "Im Bernsteinwald". - Gerstenberg Verlag, Hildesheim, 2004, ISBN 3-8067-2551-9] category and in some Mexican amber [The Gemology Project http://gemologyproject.com/wiki/index.php?title=Amber] . Any other Amber (such as Baltic Amber) will not display this phenomenon, because its original resin is not from the Hymenaea protera tree. [Larsson, S. G.: Baltic Amber - a Palaeobiological Study. - Scandinavian Science Press, Klampenborg, Denmark 1978]

The polycyclic aromatic hydrocarbons, produced through a thermal polymerization process initiated via irradiation, relax to their ground state, absorb high-energy ultraviolet photons and re-emit them as lower-energy visible photons, according to the absorbance curve of the particular fluorophore.

Recently, optical absorption, fluorescence and time-resolved fluorescence measurements in Dominican ambers have been reported. These studies show that the "blue" variety reveals an intense fluorescence emission in the visible wavelength region, between 430 and 530 nm, with spectral features which are typical of aromatic hydrocarbons. On the contrary, the Dominican "red" and "yellow" amber varieties have a much weaker and featureless emission, although still do have a certain fluorescence. The process in Blue Amber is surprisingly similar to phosphor. The difference between fluorescence and phosphorescence is basically only the amount of time that the glowing element glows.

Although there are several theories about the origin of Dominican blue amber, there is a great probability that it owes its existence to elements such as anthracene as a result of 'incomplete combustion' do to forest fires among the extinct species Hymenaea protera trees about 25 to 40 million years ago. [cite web |url=http://query.nytimes.com/gst/fullpage.html?sec=health&res=9E0CE2DD123BF936A1575AC0A964958260 |title= 40-Million-Year-Old Extinct Bee Yields Oldest Genetic Material |accessdate=2008-04-15 |last=Browne|first=Malcolm W.|year=1992|work=New York Times|language=English] [George Poinar, Jr. and Roberta Poinar, 1999. The Amber Forest: A Reconstruction of a Vanished World, (Princeton University Press) ISBN 0691028885]

Vittorio Bellani and Enrico Giulotto at the University of Pavia, Italy studied several amber specimens by means of optical absorption, fluorescence spectroscopy, and time-resolved fluorescence measurements. The resulting spectral analysis revealed that the spectra of the hydrocarbons are very similar in shape to those of diluted solutions of anthracene, perylene, and tetracene, and suggest that the fluorescent hydrocarbon responsible for the blueness is most likely

Appearance

Under artificial light, the amber appears like ordinary amber, but under sunlight it has an intense fluorescent blue glow. When held against the sun it will appear like ordinary amber, and under ultraviolet light it will glow a bright milky-blue. This effect can be compared to the ocean, which, although transparent, can appear anything from light blue to dark blue to black, depending on depth, mass, salinity, etc.

Blue amber emits a very agreeable smell (aromatic molecules), which is different from regular amber when it is being cut and polished.

Uses

Due to its rarity Blue Amber is mostly used as collector's items and high-grade jewelry, although recently it has found its way into the Arab world as highly valued worry beads (both Komboloi as well as misbahas). [cite web |url=http://www.saudiaramcoworld.com/issue/196806/worry.beads.htm |title="Worry Beads" -- The use of Misbahas in modern times |accessdate=2008-04-15 |last=Da Cruz|first=Daniel|year=1968 |month=November/December|work=Saudi Aramco World|language=English]

References

See also

* List of minerals
* Ammolite
* Copal
* Dominican amber