blue amber
{{short description|Rare variety of amber resin with a blue color}}
File:Ambre bleu dominicain 21207.jpg
Blue amber is a rare variety of amber resin that exhibits a blue coloration. Blue amber has been most commonly found in the Dominican Republic—especially in the amber mines around the city of Santiago and, less commonly, in the eastern half of the country. In the modern age, it was discovered at about the same time as Dominican amber.{{cite book |first1=Leif |last1=Brost |first2=Ake |last2=Dahlstrom |title=The Amber Book |publisher=Geoscience Press |location=Tucson |year=1996 |isbn=0-945005-23-7}}{{cite journal |first=Manuel A. |last=Iturralde-Vennet |year=2001 |title=Geology of the Amber-Bearing Deposits of the Greater Antilles |journal=Caribbean Journal of Science |pages=141–167}}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
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 emission and excitation spectra were 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 perylene.{{cite journal |doi=10.1063/1.1829395 |title=The origin of the blue fluorescence in Dominican amber |year=2005|journal=J. Appl. Phys. |volume=97 |issue=1 |pages=016101–016101–2 |bibcode=2005JAP....97a6101B |last1=Bellani |first1=Vittorio |last2=Giulotto |first2=Enrico |last3=Linati |first3=Laura |last4=Sacchi |first4=Donatella }}
Despite their findings, the presence of these aromatic hydrocarbons has not been confirmed in samples of blue amber. While all types of amber tested displayed a fluorescence, blue amber fluoresced with a greater intensity, even though the absorption extinction coefficient was larger for red and yellow amber.
File:Blue Java amber from Indonesia.jpg
Although there are several theories about the origin of Dominican blue amber, there is a great probability that it owes its existence to ingredients such as anthracene as a result of 'incomplete combustion' due to forest fires among the extinct species Hymenaea protera trees about 25 to 40 million years ago.George Poinar, Jr. and Roberta Poinar, 1999. The Amber Forest: A Reconstruction of a Vanished World, (Princeton University Press) {{ISBN|0-691-02888-5}}
This effect is only possible in some specimens of Dominican amberWilfred Wichard und Wolfgang Weitschat: Im Bernsteinwald. - Gerstenberg Verlag, Hildesheim, 2004, {{ISBN|3-8067-2551-9}} category, in some Mexican ambers from ChiapasThe Gemology Project http://gemologyproject.com/wiki/index.php?title=Amber and some ambers from Indonesia. 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
= 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.
Blue amber emits a very agreeable smell, which is different from regular amber when it is being cut and polished.{{Cite web |url=http://www.clgms.org/mar2012ss.pdf |title=Stoney statements |publisher=Clear Lake Gem & Mineral Society |date=12 March 2012 |accessdate=1 July 2015 |archive-url=https://web.archive.org/web/20160304091527/http://www.clgms.org/mar2012ss.pdf |archive-date=4 March 2016 |url-status=dead }}
See also
{{commons category|Blue amber}}
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