Amber

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Fossils / Expeditions

Amber

Amber Amber Termite Spider Flies Unpolished Amber Spider

Physical Characteristics of Amber
Types of Amber
Occurence of Amber
Physical Properties of Amber
Recovery Methods



Amber, or fossil tree sap, was made famous in the movie "Jurassic Park". Amber is a beautiful stone that is cut and polished and used as a valuable gemstone. It is also a fossil and can contain many preserved insects and other animals and plants that are tens of millions of years old. The odd inclusions that are often seen in amber usually add to amber's unique look and in many cases greatly increase its value.
The fossils that are encased in amber probably got there when they flew or crawled on to the fresh seeping sap and then got stuck. The sap oozed over the trapped animals and perhaps fell to the ground and was later covered by dirt and debris. The sap later hardened and became a fossil.
The fossils are mostly insects such as gnats, flies, wasps, bees and ants. Occasionally more exotic insects are trapped in the amber such as grasshoppers, preying mantises, beetles, moths, termites, butterflies, etc. Other non-insect animals are found in amber too such as spiders, centipedes, scorpions and even frogs and lizards. No really large animals like mammals or birds are seen in amber but feathers and fur have been seen. Invaluable plant remains have also been found in amber including flowers, mushroom caps, seeds, leaves, stems, pine needles and pine cones. The rarity of the trapped fossils controls the value of the amber more so than the quality of the amber. Remember these are fossils and are not the same species that are alive today. Amber has greatly increased the knowledge of the evolution of insects and plants as well as enlivening the interest in paleontology in general.
Amber is often imitated by plastics, colored glasses and some modern tree resins. However, its hardness is usually greater and it is tougher than other resins. Its low specific gravity (amber can float on salt water) and inclusions can distinguish it from plastics and glasses.

fly in amber

Physical Characteristics:



Amber is the fossilized resin from ancient forests. Amber is not produced from tree sap, but rather from plant resin. This aromatic resin can drip from and ooze down trees, as well as fill internal fissures, trapping debris such as seeds, leaves, feathers and insects. The resin becomes buried and fossilized through a natural polymerization of the original organic compounds.

Amber is a fossilized resin, not tree sap. Sap is the fluid that circulates through a plant's vascular system, while resin is the semi-solid amorphous organic substance secreted in pockets and canals through epithelial cells of the plant. Land plant resins are complex mixtures of mono-, sesqui-, di-, and triterpenoids, which have structures based on linked isoprene C5H8 units (Langenheim, 1969, p. 1157). Volatile terpenoid fractions in resins evaporate and dissipate under natural forest conditions, leaving nonvolatile terpenoid fractions to become fossilized if they are stable enough to withstand degradation and depositional conditions. The fossil resin becomes incorporated into sediments and soils, which over millions of years change into rock such as shale and sandstone.
Therefore, amber is formed as a result of the fossilization of resin that that takes millions of years and involves a progressive oxidation and polymerization of the original organic compounds, oxygenated hydrocarbons. Although a specific time interval has not been established for this process, the majority of amber is found within Cretaceous and Tertiary sedimentary rocks(approximately 30-90 million years old)



Although there are contrasting views as to why resin is produced, it is a plant's protection mechanism. The resin may be produced to protect the tree from disease and injury inflicted by insects and fungi. Resin may be exuded to heal a wound such as a broken branch, and resins possess odors or tastes that both attract and repel insects (Langenheim, 1969, p. 1167). In mature trees, resin may simply exude from vertical fissures in the bark due to tension produced by rapid growth (Langenheim, 1969, p. 1166). Resin may also be produced as a plant's method for disposing of excess acetate.

There is no one tree responsible for the resin that fossilizes into amber. Botanical affinities have been suggested based on examination of the entombed debris and through chemical studies of the resin. The botanical affinity of jelinite, Kansas amber, appears to be from the Araucariaceae family, which is considered to be a primary Mesozoic amber tree. Although this tree does not exist today in the northern hemisphere, it would closely resemble Agathis australis, or the huge Kauri pine found today in New Zealand.

amber time


During most of the Mesozoic geologic time period, gymnosperms dominated land vegetation. Conifers are the most successful gymnosperm living today (Cleal & Thomas, 1999, p. 62). Some of the amber land plants were probably conifers from the order Pinales, in the families: Araucariaceae (e.g., Norfolk Pine, Monkey Puzzle, Kauri Pine), Taxodiaceae (e.g., sequoias and bald cypresses), Taxaceae (e.g., yews), Pinaceae (e.g., pine and larches), Cupressaceae (e.g., cedars, cypresses, junipers), and Podocarpaceae.

Studies by Göppert (1836), based on botanical debris entombed in amber, concluded that members of the Pinaceae were the source of Baltic amber. Specifically, Göppert (1836) designated the amber tree as Pinites succinifer, although he clearly stated this wood anatomy was not the same as any living pine today. Disregarding botanical evidence and concentrating on chemical evidence, Beck (1999) and Larsson (1978) suggested sources other than Pinaceae for Baltic amber, including Araucariaceae, Cupressaceae, and Taxodiaceae; they believed that chemically Göppert's Pinites was a closer match to the Araucariaceae than to Pinaceae.

One depositional environment for amber is marginal marine. Amber's specific gravity is slightly over 1 and it floats in saltwater; therefore amber becomes concentrated in estuarine or marine deposits, moved some distance from the original site (Langenheim, 1969, p. 1159). Trees and resin may be transported and deposited in quiet water sediments that formed the bottom of a lagoon or delta at the margin of a sea. Wood and resin are buried under the sediment and while the resin becomes amber, the wood becomes lignite. Wet sediments of clay and sand preserve the resin well because they are devoid of oxygen.

Therefore, given copious resin producing trees and appropriate burial conditions, amber is preserved in sedimentary clay, shale, and sandstones associated with layers of lignite, a woody brown coal. A generalized interpretation of the depositional conditions present in Kansas amber-bearing strata is that a transgressing or advancing Cretaceous sea in north-central Kansas led to deposition and preservation of fluvial, estuarine, and lagoon or bay deposits behind a barrier island system


Types of Amber


One method of classifying amber is by color and degree of transparency. This criteria correlates to an optical classification of amber varieties. Colors of amber include yellow, orange, red, white, brown, green, bluish, and "black" (dark shades of other colors). The degree of transparency varies in amber from clear to cloudy. Clear amber is transparent and usually ranges from pale yellow to dark reddish yellow. Cloudy amber can be semi-transparent to opaque, a variety of colors and separated into terms such as fatty, bone (or osseous) or foamy (or frothy). Fatty amber does not necessarily imply a green color. Fatty amber has tiny bubbles, suspended dust particles, and is usually a translucent, yellowish color resembling goose fat or also compared with the look of whipped honey. Green amber has tiny bubble inclusions and suspended particles, but it does not have the yellowish appearance of fat. The green color probably results from decaying organic matter in a marsh environment. Bone or osseous amber is whitish yellow or brown in color, opaque and looks similar to ivory or bone. Black decayed organic debris is commonly found in this type of amber. Foamy or frothy amber is very soft and therefore incapable of taking a polish. It is opaque and usually contains pyrite infilling cracks.


Natural lumps of amber formed from resin extruded inside and outside the tree trunk. These forms create external drippings and swellings, as well as internal resin which gathers in fissures inside the tree trunk.



1. Internal crack fillings
2. Forms under the bark
3. Resin pocket in the wood
4. Forms between the bark
5. Fillings from tree wounds
6. External stalactite shapes
7. Stalactite
8. External drops and swellings
This was taken from Lausitzer Bernstein (1995) by B. Kosmowska-Ceranowicz, et.al.



Other descriptive names for amber exist, reflecting not only color and degree of transparency but also chemical composition, the degree of weathering, places of discovery, workability, and functions in folk rituals. In Poland, some 200 folk names are applied to amber and some 80 variety names. "Soily" amber is described as brown or green, and full of gas bubbles and debris due to the decaying organic matter.
Another mode of classifying amber, a physical classification, is based on procurement, land or sea. Sea stone and scoopstone refers to amber found in or near the sea. Scoopstone is the amber gathered from seaweed. Sea stone or sea amber is collected as it is washed onto the beach or directly from the water (amber floats in salt water). Some amber procured on land is termed pit amber. Pit amber is mined from rock strata called "blue earth" and the source of most Baltic amber. This amber is covered with a crust, which obscures the quality of the piece. Sea amber is usually superior to mined amber because the waves provide polish, a uniform quality and there is no crust on the surface. Amber can also be found on land in secondary or alluvial deposits. Alluvial deposits indicate the material has been transported away from the primary source by erosional agents such as wind, water or glaciers.
Another physical classification system is the natural form in which amber is found. There are both external and internal tree trunk amber forms. External amber forms are the result of resin extruded by the trunk. This creates various shapes and sizes that can preserve trunk imprints as well as debris. Internal amber forms are the result of resin infilling fissures and extended wounds within the tree trunk. These casts (filling in a mold) can be large lumps or tiny, flat plates with imprints on both the convex and concave surfaces. The lumps can originate during the healing of wounds, such as broken branches, and the flat plates could be filling cracks or resin pockets between annual growth rings. One external dripping form can be termed a stalactite, elongate and conical, with a somewhat concentric structure resulting from multiple outpourings of resin. Internal crack filling forms can also be elongate, but the structure shows the axis is parallel to the direction of flow, not concentric.
Finally, amber can be classified based on chemical composition , usually as one of two fossil resins: succinite or retinite. Baltic amber or succinite was once thought to be the only "true" amber and is the most suitable for jewelry. Other fossil resins include gedanite, krantzite, beckerite, stantienite, glessite, schraufite and delatynite. These fossil resins are mostly devoid of inclusions and contain small amounts, if any, succinic acid. Gedanite is found with Baltic amber and thought to be resin from an extinct white pine species. It was first found near Gdansk, which is now in Poland but then called Gedania. Krantzite and gedanite are both rare varieties of Baltic amber, that is they contain some succinic acid, but both have lower hardness and other differing properties from Baltic amber or succinite. Beckerite is also found with Baltic amber, though nicknamed "brown resin". Stantienite resembles beckerite in color but due to complete opacity it is termed "black resin". These two types of amber are named for Becker and Stantien, two developers of amber dredging and mining operations in the Samland region in the 1800s.


Geologic Occurrence of Amber


The composition, color, and other physical properties of amber all vary according to age, conditions of burial, and type of tree that produced the resin. Amber has been found in sediments from the Carboniferous to Quaternary age, but the greatest concentration is in Cretaceous and Tertiary sediments. Below is a geologic time frame relating to amber formation, based on Jean Langenheim's work with amber/botanical affinities reproduced in Rice: Amber the Golden Gem of the Ages, the Polish Academy of Sciences: Amber in Nature, a German publication: Lausitzer Bernstein, and Grimaldi: Amber Window to the Past. Mark Meyer has created a timeline for the presence of amber within the geologic time scale that is worth visiting too! It is difficult to determine if the amber in sediments is primary or secondary. Primary deposits are insitu. Secondary deposits are where amber is found after transportation by rivers, transgressing seas, glaciers or fluvioglacial waters. Up until 1860 amber procuring methods were off the beaches and with shallow diving. It was obvious that sea amber came from strata beneath the sea and a larger supply could be obtained by dredging or mining. Most Baltic amber is being produced in the Samland promontory, an area today controlled by Russia, where the strata containing amber is approximately 25-40 meters beneath the soil. A typical, geologic cross-section representing undisturbed, amber-bearing strata along the Baltic coast would include: less than a meter of alluvium; four meters of Pleistocene sand and marl (1-2 mya?); seventeen meters of Tertiary sands and lignite (2-5 mya?); one-three meters of Tertiary coal (2-5 mya?); seventeen-twenty meters of glauconite (5-25 mya?); and finally the Tertiary layer with amber, five to six meters of "blue earth" stratum (25-40 mya?). Below this "blue earth", a gray-green clay is Cretaceous age rock, which in this location is devoid of amber.



Controversy exists regarding the geologic age of some resins, and whether or not all fossil resin may be considered amber. If hardened resin is collected in Tertiary, Quaternary, or Recent primary deposits, not secondary reworked alluvial deposits, that are less than 25-35 million years old, there is a good chance that this fossil resin, or the so-called amber, is in fact copal. Resins that have been dated to be a few hundred to a few million years old are copal not amber.

Physical Properties of Amber


A mineral is a naturally occurring homogeneous solid with a definite chemical composition and ordered crystalline structure. It is usually of an inorganic origin. Amber is not a mineral, because it has an organic origin and amorphous structure (no orderly internal arrangement of atoms). Find out more about amber's physical properties below. Information is available on a young resinous material, that is often times confused with amber, called copal. Copal resembles amber but is not a mineral either.

Composition: can vary greatly depending on the botanical source, though all have terpenes or compounds that are linked as the resin matures. It is thought that Baltic amber, or succinite, contains 3-8% succinic acid (succus is Latin for juice); succinic acid is believed to form from microorganism-induced fermentation of the cellulose contained in the resin. One composition of an amber variety is: oxygenated hydrocarbon (carbon 67-87%, hydrogen 8.5-11%, oxygen 15%, sulfur 0-0.46%). Although this composition was believed to be the hardened tree resin from the genus Pinus, chemical studies show these pines were not the source of Baltic amber.

Dr. Curt W. Beck (1998) summarized the literature on the chemistry of amber at the World Amber Congress. He related Pliny's belief that amber was a liquid seeping from pine, hardened by frost, heat, and the sea. In the 16th century, Agricola also believed amber to be the juice of a pine tree and used the term succinum. Although botanists have described the Baltic amber tree as Pinites succinifer or from the genus Pinus, based on cones and needles found entombed amber, the chemists have isolated compounds in succinite that occur in other sources than ordinary pines. In the 19th century Germans, Swedes, and Swiss chemists recognized succinic acid and borneol, among other compounds, in amber. Only recently though, has decisive work on resin constituents been accomplished with a combination of mass spectroscopy and pyrolysis gas chromatography. Chemical analysis of succinite has concluded a "labdanoid character" for this fossil resin, based on work by

Ken Anderson and others; this analysis eliminates the botanical source of the genus Pinus for Baltic amber (Beck, 1998, p. 57). Dr. Beck and Dr. Francis Heuber (personal communication, 1998) believe the botanical source for succinite to be araucarian in origin. Although the tree does not exist today, it is related to Agathis australis or the huge kauri pine tree found in New Zealand

Color: varying shades of yellow, orange, red, white, brown, green, bluish, "black" (deep shades of other colors). Rainbow colors within the amber are caused by the light interference of air bubbles or strain created during an insect's death struggle. Some believe the color is related to the type of tree source. Recent pine trees produce golden yellows, white, ivory-colors, and occasionally a blue resin. Scientists at the Polish Museum of Science believe that reddish tints are the resin of deciduous trees, such as cherry and plum. Dominican amber with a reddish tint is thought to be related to a leguminous source.

Amber color preferences vary from country to country. The transparent reds and greens are thought to be the most desirable colors in some countries, followed by the transparent yellows. The warm, transparent, orange color seems to be a desirable color for many Americans. Natural amber, regardless of color, may darken to a mellow brown after long exposure to air; pressed amber may turn white as it ages.
More information on amber colors is found at Gintaro Galerija Muziejus and at Dragonfly Amber.com, which includes an amber color chart.

Classification & Structure: organic & amorphous.

Transparency: all graduations from perfectly clear to wholly opaque, with cloudy turbidity due to the presence of numerous air bubbles and inclusions. The air in amber is the subject of study also! See Air bubbles, amber, and dinosaurs by Gary Landis and Dinosaur breath by John G. Cramer.
 
Hardness: 1-3. Burmese amber, or amber from Myanmar, is the hardest at 3 on the hardness scale; Baltic amber is usually in the range of 2-2.5; Dominican amber is the softest at 1-2. Geologically younger amber tends to be softer than amber that has been buried for a long time.

Tenacity & Fracture: tough to brittle, conchoidal fracture. For its low hardness, amber is remarkably tougher than most gemstones of a similar hardness. Baltic amber tends to be tougher than retinite amber; Dominican amber tends to be more brittle and break more easily than other ambers.
 
Luster: resinous.

Specific Gravity: 1.05-1.2 (is buoyant, staying afloat in water saturated with salt or sea water). The clearest or transparent ambers are more dense, whereas amber varieties containing numerous air bubbles and are less dense.

Fluorescence: some pieces fluoresce. The common fluorescent colors of amber are blue or yellow, and less frequently a green, orange, or white. In general, resins with higer sulfur content fluoresce more than those containing less sulfur.

Recovery Methods


While some people were fishing for food or pearls, others were in search of the "gold of the north". People did fish for amber in the past. There is a drawing, first published in Philip J. Hartmann's book from 1677, which shows fishermen fishing for amber! The sea is the oldest known source for amber. Prehistoric people picked up amber from the Baltic shore, when strong storms and winds brought the material up from amber-bearing strata under the sea. Sea amber or scoopstone has provided a livelihood for coast-dwellers for many centuries. Amber was named scoopstone because of the nets used to gather it from the seaweed. These poles and nets, called "amber-catchers," were first detailed in the Hartmann book. In marshy regions or areas where the tides were unpredictable, amber was collected on horseback. These collectors were called "amber riders". Hartmann also described "amber divers" in his 17th century book. The divers carried a wooden spade to loosen the amber from the sea floor. A method of collecting amber in an 1892 publication was from broad-beamed rowboats. Fishermen would lay over the side of the boat, rake the bottom and then catch the dislodged lumps of amber in nets. In some areas large boulders were hauled up from the sea floor to be used as building stones. Amber was recovered and this method was referred to as "amber poking".
In 1854 Whelhelm Stantien obtained a lease from the government to dredge for amber. In 1869 Mority Becker joined Stantien to form the business, Stantien and Becker. They continued increasing their dredging operations and provided divers with modern equipment for picking amber off the sea floor. They were working in the Prussian province of Samland, which is today the Kaliningrad Oblast, Russia. Geologists had determined the glacial debris containing amber in Germany, Denmark, Poland and other Baltic lands derived from the blue earth or a Tertiary glauconite formation found in this area. In 1870 Stantien and Becker purchased the right to mine on land for amber. They built dams to keep the sea back, as the stratum was below sea level. In 1895 their operation produced a record high of 1,200,000 pounds (over 540,000 kg) of amber. The government bought them out in 1899 and once again all amber became the property of the state. The government operated this Stantien and Becker mine until 1925.
Other mines continued operation with modernized mining and recovery techniques. Many of the mines were open-pit operations where the blue earth was scooped onto conveyers to rail cars. The cars were emptied into the spray house, where pressurized water flushed the amber from the soil. World War II temporarily halted amber production and by the mid-twentieth century most Baltic amber was under Soviet control. For more information regarding amber recovery and environmental degredation, see D. Jacobson's work, Amber Trade and the Environment in the Kaliningrad Oblast.
In early times, amber was the absolute property of the finder. As amber became a lucrative business in the Baltic region, dukes, kings, Teutonic knights and different countries tried to control the collection and sale of this commodity. Fishing rights were granted and rescinded by the "Amber Lords" as early as 1264 A.D. When amber was collected without supervision of a "Beach Master" or "Beach Rider", the unauthorized persons were hung. Amber guilds were formed in the 14th century to create rosaries and works of art from the raw material supplied by the Amber Lords. In the 17th century, fishermen had to swear to the "Amber Oath", which denounced amber smugglers, and searching for amber was not an option but a requirement. Some amber fishermen were paid in salt (interesting link though not directly related to amber and the site loads slowly) for their raw amber, weight for weight.