This is what Roman scientist Pliny the Elder wrote about the value of amber at the very beginning of the first millennium:
"...neither white amber that was used as a fragrant incense nor turbid yellow or dark was as valuable as transparent, slightly glossy amber. If you held a piece of such amber to a fire, you would see only reflection rather than the flame itself (...) Most popular was transparent amber having the shade of Falernian wine. It was the most expensive (...) Amber was made whiter by immersing it into preheated goat fat with alkanet dye."
Baltic amber is very colourful. Usually Baltic amber is yellow or bright yellowish. Colours of amber range from white, yellow, brown to red. There is greenish, bluish, gray and even black amber. Even more subtle shades and combinations are among them. Amber can be absolutely transparent or absolutely opaque. Amber is not always one-coloured: unique combinations of two or more colours and shades, patterns (sometimes they form the most brilliant compositions of art) can be found. That is why amber becomes attractive, charming and unique.
Natural amber has a thin bark. After we polish it, natural color of amber shows up. Baltic amber has seven main colors, and about 250 shades.
Tree resin is the main amber material. It can be transparent, bright yellow - colour of fresh honey. This colour (clear amber) remains after the resin transformed into amber, however, variations in the resins could affect it:
Various impurities and main structural amber elements - very small turpenine gas bubbles - changed colour of amber. In a certain density and form it defracts the light, which is seen as some kind of colour.
Transparent amber (with a yellowish shade). About 10% of amber are transparent, but this is mostly found in small pieces. Big transparent amber pieces are especially rare and valuable. This colour of amber could be called "primary"- fresh tree resin looks like this. Resin was flowing somewhere in a shady place; that is why turpens, the volatile components of resin evaporated slowly and did not make the resin turbid with gas bubbles, so the amber remained transparent. The shade of transparency could change from yellowish to dark red; it depends on the degree of amber oxidation. If successive streams of resin were laid in layers, the amber was formed foliated. Most inclusions are found in this particular amber.
At the end of the 18th century almost colorless transparent amber was used in the manufacture of optical products. In 1691 artist Persian Christian made amber lenses and spectacles for the first time. The time scientists said that amber optics is of higher quality than glass one. But the glass optics is harder. The last report on the use of amber glass spectacles dates back to 1835 report from London.
Red amber. Natural red shade is especially rare. Red shades can vary from orange to dark red. Red amber was formed when the amber stayed in the air for a long time: oxidation process, heat of the sun, fire in the forest. Natural oxidation takes place in the air and the amber interacts with oxygen and changes its colour step by step. Transparent amber becomes more red; yellow and other colours become more concentrated. This is very long process: change in the shades of colour could be noticed only after 50-70 years. "Old" amber is highly valued because of its "maturity“ and has its time patina. Red colour of amber is mostly obtained artificially by heating transparent amber (oxidizing it), but heated amber loses its natural properties.
Red amber named “dragon’s blood” was widely featured in Shosoin treasures found in
Yellow amber. This is the most common colour of amber (about 70% of all colours). Resin was flowing from trees in the heat of the sun and the volatile components of resin evaporated and made them turbid - thousands of small gas bubbles were formed. These bubbles defract the light forming the yellow colour. In one square millimeter of yellow amber could be 2500 gas bubbles
Yellow amber is an inherent part of national female costume. It was previously used in marriage rituals, mounted to the crib, in the Stone Age amulets of yellow amber were produced, because it was believed that yellow amber is like a stone of the sun. Prof. M. Gimbutienė‘s view, yellow and white color simbolizes a death in the old symbolism. Yellow amber was used to produce images, figures and amulets of the mythical death goddess.
White amber is very rare. Usually this amber is distinguished by its variety of textures and "natural ornamentation". Amber of this colour is also called "Royal" or "Bony", some people take white amber for ivory. It can be with some "colourful intrusions" (yellow, black, blue, green, transparent amber) with interesting patterns. The volatile materials of resins evaporated very intensively in the sun heat and resin obtained the form of foam. In one square millimeter of white amber there could be about 1 million micro-bubbles
In ancient times white amber was used to produce expensive medicine. They were used to treat heart ailments. The constituent components of this product included: white amber, red coral, roots of Rubiaceae, deer horn, pearl and black crab claws.
Blue amber. This is the rarest shade of amber and the most valuable. Less and less bluish amber could be found, so this color became now almost extinct. Very rarely blue amber is found, probably just two pieces of a thousand. Blue amber formed when resin floated by the rivers to the peninsula of Sambia and it got into soil saturated by pyrites (FeS2). Intrusions of pyrites got into small cracks of resin. Most frequently this shade is found in white amber. Blue Baltic amber differs from the blue Dominican amber. Bluish shade is visible in the Dominican amber only by a special light.
In ancient times the chief priest wore white bluish amber with inclusions. This shade attracted the blessing of the gods and correct predictions. It helped them to work with spirits of water, land, air and fire.
Greenish amber is also rare. Greenish shade and sometimes "crystal"/"sugar" structure was formed, after resin fell on plants and reacted with pigment chlorophyll that could be found in plants. Because of the crystal structure, sometimes green amber is called "sugar" amber.
In ancestral times, priest's assistant - a herbalist - wore amber with herb motifs. Amber of this shade helpped him to talk to spirits of the world's flora and select necessary plants.
Black amber. This is a rather frequent colour of amber. Resin was thoroughly mixed up with the remains of the bark and leaf litter mass. Sometimes there could be only 10-15% of resin, and the other being impurities. Therefore, black amber is more fragile than other colours of amber and it is difficult for artists to work with it.
Earlier, the priest used black amber or powder of black amber, if enemy wanted to attack. It was a ritual, which had to mislead enemy in forests and swamps. Black amber has also been placed on the chest of the deceased. It had to protect the soul from attack of evil spirits and lead to the world of dead. A. Mateson from Riga, had extrasensoric abilities and found that black amber is energetically more active, so it is recommended to wear beads of black amber for people, who have problems with the throat, especially thyroid.