Natural and Rare Baltic Amber Colors
One of the most fascinating aspects of Baltic amber (second to insect, flora, and fauna inclusions) is its wide color spectrum. Most buyers are surprised when they see a display of Baltic amber jewelry from Poland and discover that the gem naturally occurs in 250 colors. WOW! This spectrum in amber jewelry complements almost any color of clothing.
Descriptive terms to name the colors of amber came from the antique trade. Picturesque names such as "goose fat," "egg yolk," and "cherry" were based on transparency and color. Other descriptive words include: "banana," "ivory," "milky," "lemon," "sunny," "custard," "honey," "cognac," "molasses," "greenish," "orange," "brown," and "black." The rarest colors of natural amber are blue, green, white, and "kumst" (sauerkraut color). Jewelers in the Polish amber industry have over 200 names for their national gem.
What determines the natural color of Baltic amber? The two factors are:
1. The microscopic bubble inclusions of gas within the gemstone.
2. The tree source.
The gas bubbles vary in size and quantity within each piece. In the space between these bubbles, the resin is clear. The bubble inclusions actually interfere with the passage of light through the amber. This interference results in the dilution and variations in color and turbidity (opaqueness).
Studies have shown that a comparison between the colors of fossil resin and recent resin suggests that certain colors come from certain tree sources.
Heat-Enhanced Amber Colors
As far back as the first century, it was known that cloudy amber could be clarified by boiling the gem in the fat of a suckling pig. Later, it was discovered that other oils could be used, the most common being rapeseed oil. The refractive index of rapeseed oil is the closest to that of amber. The amber is immersed in an iron pot of rapeseed oil and slowly heated to the point of boiling. The microscopic air bubbles then become filled with the oil. This makes the amber transparent, as the light is able to travel through the gem without interference. The small circular fissures in the amber are encapsulated water droplets that flatten to disk-like shapes when the amber is boiled. These disks are commonly referred to as "sun spangles" or "fish scales." The amber must then be cooled very slowly or it could fracture easily.
Brilliant Green Baltic Amber On Today's Market
At jewelry and gift shows throughout the country today, you will often see brilliant green amber gems set in sterling silver. This is Baltic amber, but it has been heat enhanced. As with most gems, there are enhancement techniques to enliven and brighten the stone. Remember, the natural green amber is rare and would not be so bright with inclusions and "sun spangles." Currently, jewelers are applying a dark paste (almost like a paint) to the backs of the amber gems. They then heat the amber in an autoclave to clarify it and cause the fractured discs. The illusion of the dark paste through the honey-colored gem causes the beholder's perception of green amber. Another heating method is used to create the cherry color of amber. The heated amber is still considered gem quality. Milky, creamy, and lemon amber are examples of natural colors which have not been heated—obviously, you don't see the "sun spangles."
Whatever amber color is your favorite—enjoy its special qualities because no two pieces are exactly alike!