Amber samples with warm colors act as a three-dimensional window that allows scientists to recreate ancient ecosystems through the countless animal and plant inclusions it contains.
Accumulated over tens of millions of years, fossilized tree resin, known as amber, has captivated jewelry makers and inspired scientific research.
Fossilized resin from coniferous trees can turn into amber over millions of years. (Image: ICA)
For the past 200 years, paleontologists around the world have used amber to understand ancient history by studying the preserved fossils within it.
How Amber Forms
Amber is essentially the resin of ancient coniferous trees, a warm-toned liquid that oozes from trees that are sick or have wounds in their trunks.
This complex, sticky substance is insoluble in water and hardens upon contact with air, forming a protective layer over the tree’s wounds, helping to fend off fungi and other pathogens.
Due to its adhesive properties, small creatures can become trapped in the resin as it seeps from the tree bark, drips to the ground, or falls into water, where these resin droplets may be buried in place or washed away to rivers or seas.
Over time, as these resin droplets are buried in sediment, they undergo numerous changes and transformations under pressure and heat to “mature,” becoming a dense, rock-like, glass-clear molecular structure that we call amber. It can also preserve the shape of any organism trapped within it with remarkable integrity from shape to structure.
Amber is found in 7 main colors and 300 different shades. The most common color remains orange-yellow, similar to honey. Rarer colors include red, green, and the particularly precious blue.
Only about 10% of amber is transparent, while the remaining 90% is opaque. These different colors are determined by the source of the natural fossilized resin and the types of inclusions within.
The oldest amber on Earth—found in the coal seams of Illinois, USA—is approximately 320 million years old, long before the dinosaurs appeared.
However, these amber pieces average less than 1/4 inch in width and do not contain any fossils inside.
According to the International Colored Gemstone Association (ICA), amber must be at least 40,000 years old, while the Gemological Institute of America (GIA) claims it takes 1 million years for tree resin to turn into amber.
Amber containing the inclusion of the crab Cretapsara athanata from 100 million years ago discovered in Myanmar. (Image: LIDA XING)
Specific information is still being researched by scientists, but all agree that it takes at least 40,000 years for a fossilized resin sample to become amber.
If it is younger than that, the material is likely classified as copal – a type of “young” fossilized tree resin that retains some characteristics of newer material, such as a stickier surface.
Amber Around the World
Amber and copal are found at 160 locations worldwide, but only about a few dozen sites contain amber with fossil inclusions.
Most of these fossil-bearing deposits date back about 125 million years or younger, except for a 230 million-year-old amber deposit in the Italian Alps that preserves a species of fly and two ancient tick species.
Any species of flora or fauna can be “preserved” in amber, either partially or wholly, from flowers and leaves to insects and vertebrate animals surrounding the environments of the resin-producing trees.
Warm-colored amber samples have served as a three-dimensional window for scientists to recreate ancient ecosystems through countless inclusions of flora and fauna.
For nearly two centuries, paleontologists studying amber have discovered about 1,300 species of flora and fauna, including extinct species, from lizards, insects, spiders, crabs, to leaves, flowers, fungi, microorganisms, feathers, and other plant debris.
Currently, there are four famous amber deposits around the world that are extensively studied.
Baltic Amber
The Baltic region is home to the largest known amber deposits, known as Baltic amber or yellow amber. It is estimated that these forests produced over 100,000 tons of amber.
Dating from 34 to 38 million years ago, they contain over 3,500 species of fossilized arthropods, including more than 650 species of spiders.
Baltic amber containing the gecko Yantarogekko balticus dating back about 54 million years. (Image: WOLFGANG WEITSCHAT)
Rarely does Baltic amber contain vertebrate animals, but a piece of amber containing an inclusion of a Yantarogekko balticus gecko dating back about 54 million years has been discovered.
Additionally, scientists have also found in Baltic amber the fossil of the largest flower species ever discovered.
Dominican Amber
Dominican amber differs from Baltic amber in that it is more transparent and has a higher number of fossil inclusions. This has allowed for detailed reconstruction of the ecosystem of a long-extinct tropical rainforest.
In addition to the common yellow and honey colors, Dominican amber also comes in red and green, with fewer occurrences, especially rare blue (fluorescent) amber.
Dominican amber is believed to be between 15 to 20 million years old, although the exact age is still a topic of debate.
Scientists have found over 1,000 species of fossilized organisms in amber here, including over 400 species of insects and 150 species of spiders. Occasionally, fossil inclusions of vertebrates, including a species of salamander, are also found.
Myanmar Amber
Myanmar amber is about 99 million years old and is mined from deposits in Kachin State, northern Myanmar, where it has been harvested and supplied to the jewelry industry for the past 2,000 years.
An immature tick clinging to a dinosaur feather preserved in 99-million-year-old Myanmar amber. (Image: National Geographic)
In the past two decades, interest in Myanmar amber has increased as paleontologists have discovered an incredibly diverse ecosystem found within the amber here. This includes amber containing a carnivorous ant “frozen” in the middle of a meal, part of a feathered dinosaur tail, the shell of a marine creature known as ammonite, and even a fossilized baby bird.
Canadian Amber
Canadian amber dates from 78 to 79 million years ago, primarily found in the Grassy Lake area of Alberta in western Canada.
Scientists have found over 130 different fossil specimens in the amber here, many of which are ticks or aphids. Some other amber samples also contain fragments of conifer leaves, fungi, pollen, and even feathers from birds or dinosaurs.
By preserving organisms intact for tens of millions of years without being affected by physical and chemical agents in the environment, amber has helped to retain a portion of Earth’s history. David Federmand, the author of a book on gemstones, says: “Amber is like a time capsule created by Mother Nature and placed on this Earth.”
