Blue amber is a rare variety of

amber Amber is fossilized tree resin that has been appreciated for its color and natural beauty since Neolithic times. Much valued from antiquity to the present as a gemstone, amber is made into a variety of decorative objects."Amber" (2004). In Ma ...

resin that exhibits a blue coloration. Blue amber has been most commonly found in the

Dominican Republic The Dominican Republic ( ; es, República Dominicana, ) is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean region. It occupies the eastern five-eighths of the island, which it shares wit ...

—especially in the amber mines around the city of

Santiago Santiago (, ; ), also known as Santiago de Chile, is the capital and largest city of Chile as well as one of the largest cities in the Americas. It is the center of Chile's most densely populated region, the Santiago Metropolitan Region, whose ...

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 Dominican amber is amber from the Dominican Republic derived from resin of the extinct tree '' Hymenaea protera''. Dominican amber differentiates itself from Baltic amber by being nearly always transparent, and it has a higher number of fossil inc ...

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 Anthracene is a solid polycyclic aromatic hydrocarbon (PAH) of formula C14H10, consisting of three fused benzene rings. It is a component of coal tar. Anthracene is used in the Economic production, production of the red dye alizarin and other dyes ...

perylene Perylene or perilene is a polycyclic aromatic hydrocarbon with the chemical formula C20H12, occurring as a brown solid. It or its derivatives may be carcinogenic, and it is considered to be a hazardous pollutant. In cell membrane cytochemistry, ...

, and

tetracene Tetracene, also called naphthacene, is a polycyclic aromatic hydrocarbon. It has the appearance of a pale orange powder. Tetracene is the four-ringed member of the series of acenes. Tetracene is a molecular organic semiconductor, used in organic ...

, and suggest that the fluorescent hydrocarbon responsible for the blueness is most likely

. Fluorescence is the process where molecules absorb high energy light which excites electrons into higher energy molecular orbitals. As these electrons relax back into their ground states, the energy difference is released as a photon, therefore emitting light at a higher wavelength or lower energy than the originally absorbed light. 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. Blue Java amber from Indonesia

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

as a result of 'incomplete combustion' due to forest fires among the extinct species ''

Hymenaea protera ''Hymenaea protera'' is an extinct prehistoric leguminous tree, the probable ancestor of present-day ''Hymenaea'' species. Most neotropical ambers come from its fossilized resin, including the famous Dominican amber. ''H. protera'' once grew in ...

'' trees about 25 to 40 million years ago. This effect is only possible in some specimens of

category, in some Mexican ambers from

Chiapas Chiapas (; Tzotzil language, Tzotzil and Tzeltal language, Tzeltal: ''Chyapas'' ), officially the Free and Sovereign State of Chiapas ( es, Estado Libre y Soberano de Chiapas), is one of the states that make up the Political divisions of Mexico, ...

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 ''

'' tree.

Appearance

Under artificial light, the amber appears like ordinary amber, but under

sunlight Sunlight is a portion of the electromagnetic radiation given off by the Sun, in particular infrared, visible, and ultraviolet light. On Earth, sunlight is scattered and filtered through Earth's atmosphere, and is obvious as daylight when t ...

it has an intense fluorescent blue glow. When held against the sun it will appear like ordinary amber, and under

ultraviolet light Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...

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

References

{{DEFAULTSORT:Blue Amber . Mining in the Dominican Republic Natural history of the Dominican Republic

Causes of coloration

Appearance

See also

References