Amber is the hardened resin of coniferous and angiosperms trees (3,5). Resin is not to be confused with sap which is a product of photosynthesis that
consists of sugars, water and dissolved minerals. The sticky extrusive mass that comes from a cut on a pine tree is resin. Under the proper conditions the resin undergoes certain physical and chemical changes that turn it into amber (2). If the resin has hardened in recent times, it is called copal. Presently certain trees produce large quantities of resin; the Kauri gum from New Zealand (Agathis australis), Sundarac from Australia (Tetraclinis articulata), the Gum Arabic tree from Africa (Acacia arabica) and the Algarroba tree from South America (Hymenaea courbaril). It was trees like these which produced the resin that often trapped unsuspecting insects and even larger animals. Like fly paper, the more one struggled to get free, the more entangled it became.

Each locality produces amber of a distinct type. Often the location of the amber can be derived visually from the amber itself. Baltic amber may have a cloudy appearance, due to air bubbles. The thicker the flow, the more bubbles that remained. The thinner the flow, the fewer the bubbles(2). Baltic amber also has a high percentage of succinic acid, as much as 8% by weight. In addition this amber often has stellate oak hairs. Fifteen varieties of trees have been recognized so far from these hairs (5). White amber (clear) has been found in Tasmania and is estimated to be about 2 million years old (6). Dominican Republic amber, around 25 million years old, has little succinic acid in it; the color is usually clear yellow; is a bit harder than other amber; and it commonly has ants and beetles as inclusions (2). Spectral analysis can reveal the location and age of most amber.

Amber comes in many
colors. Typically amber golden yellow, but can also be green, red blue and clear. Surprisingly, it is relatively stable and is insoluble even in many organic solvents. It has a specific gravity of 1.05 to 1.09 and therefore floats - it should sink if the specific gravity is greater than 1 (5). The Greeks believed that amber was the petrification of sunrays; some even felt that it was petrified tears. They prized amber for the magical properties that electricity exhibited when rubbed (2). The term electricity is derived from the Greek word, elektron, which is also the Greek word for amber (3). In modern times different uses for the "petrified sunlight" have been found. In the 1800's amber was melted and used as a finish on sailboats and other marine ships. Larger pieces of amber have been used by artists for sculpturing. Some has been melted down and re-solidified into ambroid for costume jewelry. The better quality amber was and often is polished and used for jewelry.

The selective entrapping of insects and other small animals is a fascinating aspect of the fossil. Large animals are often strong enough to break free of the sticky resin, while small insects such as ants, bees, beetles and mites are usually not strong enough to break free from its hold. It is for this reason that animals most often-found in amber are Arthropods. In New Jersey the oldest ants (workers) have been found, dating from the Cretaceous period, confirming that sociality has existed as far back as 100 million years ago. It is with these small animals that many questions for modern scientists are revealed.

Bacteria that existed millions of years ago are probably still in and on the trapped animals. Could they still be alive? Might they carry disease organisms that have long since become extinct? Could they carry resistant plasmids that scientists may be able to use? In March of 1982 in Science magazine, Roberta Hess and George Poinar, Jr. announced that the discovery of cellular components in embedded insects.

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Below is the NEW Amber Cam!
Actually this is a live image of the United States Air Force Academy
and Pikes Peak! It is located on top of Amberica West

Pikes Peak Cam

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They found such cellular detail as nuclei, ribosomes and chromosomes (6). Their efforts to try and sequence the possible DNA failed. However, since then many advances in DNA cloning have occurred. In particular the polymerase chain reaction (PCR) which allows millions of copies of DNA to be made from a very small original sample in a short time. Now, even DNA from
fingerprints can be analyzed. Could we clone an ant with the small amount of material left? What about mites and other parasitic creatures that infected dinosaurs and other prehistoric animals? Might they have blood and skin from their hosts? Would it be possible to clone a dinosaur from a few cells in the gut of a mite?

One unique thing about inclusions in amber is that the animals are not fossils in the classic sense. Most fossils are the imprint or bony remains of an organism. Amber has the actual animal itself! While usually all that remains is a carbonaceous crust, sometimes soft parts do survive (3). Recently even the air bubbles that reside in different ambers have been analyzed to determined the composition of an atmosphere at that time. It is with these that the future dreams of research reside.

When students view the sample, the same excitement that I have always felt surges through them. My students are always interested in the "real-life" aspect of the fossilized insects. Showing the amber sample and relating it to the geologic time line, or life as it was in the prehistoric time is particularly effective. With an over head projector, a dissecting microscope or just hand held observation, students experience awe in seeing the real creature. Students can readily acquire their own samples as amber, with inclusion such as insects and other organic debris, is available at rock and mineral shops from $20 to $60 a sample. It is with amber that one can easily see into past life. It combines beauty and history. It is truly a golden eyepiece to the past.

(1) Langenheim,
J. H., (1990) Plant Resins. American Scientist, -48(1): 16-24.

(2) Poinar, G.O., Sealed in Amber. Natural History, 9(6):26-32.

(3) Gorman, James. (1982) The 40-Million-Year-Old Bug. Discover,
May:36-38.

Eugenio Ragazzi has pointed
out that pages 40 - 45 present another article on amber, "Golden Oldies",
which has good pictures of insects in amber.

(4) Grimaldi, D. A. (1988) Still Life with Flowers. Natural History,
8:86-90.
(5) Burnham, L. (1980) Amber. Horticulture, 2:24-31.
(6) Pellegrina, C. R. 1985, Dinosaur capsule, Omni, -4(1):40-43.