Blue amber is a rare variety ofamber resin that exhibits a blue coloration. Blue amber has been most commonly found in theDominican Republic—especially in the amber mines around the city ofSantiago and, less commonly, in the eastern half of the country. In the modern age, it was discovered at about the same time asDominican amber.[1][2][3]
Vittorio Bellani and Enrico Giulotto at theUniversity 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 ofanthracene,perylene, andtetracene, and suggest that thefluorescent hydrocarbon responsible for the blueness is most likelyperylene.[4]
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.
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 asanthracene as a result of 'incomplete combustion' due to forest fires among the extinct speciesHymenaea protera trees about 25 to 40 million years ago.[5]
This effect is only possible in some specimens ofDominican amber[6] category, in someMexican ambers fromChiapas[7] and some ambers fromIndonesia. Any other amber (such asBaltic amber) will not display this phenomenon, because its original resin is not from theHymenaea protera tree.[8]
Under artificial light, the amber appears like ordinary amber, but undersunlight it has an intense fluorescent blue glow. When held against the sun it will appear like ordinary amber, and underultraviolet 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.[9]
