By Pat McNear and Janice Reynolds
Amber, the material man has used for personal adornment longer than any other, keeps good company in its category of non-mineral jewels: diamonds, pearls, coral, jet and ivory which are also organic gems. Each has had its share of imitations, but there are probably more varieties of would-be amber than any other counterfeit. Many different substances, both natural and synthetic, have masqueraded as this unique and valued resin.
Amber is the fossilized sap of ancient trees and is found in various locations world-wide. The age and chemical composition of the resin differs from area to area. The age of Baltic amber is estimated at 40-60 millions years, and the sap originally came from the giant conifer Pinus succinifera. The substance is found in a range of colours from white to near black, most Baltic amber is yellow, gold or light brown. Amber's clarity varies from transparent to opaque. All of these variables were affected by the condition of the sap itself, the soil onto which it fell and the climatic and geological conditions which prevailed during the ensuing eons. The variety of colour and the unique nature of each piece of amber satisfy the current desire for individuality and are in good part responsible for its resurgence of popularity today.
The softness of amber (approximately 2.5 in the Mohs Scale: harder then alabaster but softer than calcite) made this fossil resin uniquely suited to being worked with primitive tools in the hands of early men attracted by the golden, sun-reflecting stones washed up on the beaches. The use of amber in jewellery dates from the prehistoric period. Amber beads and amulets have been found in stone age tombs all along the Baltic Coast, in Ireland and England and as far as south of the Adriatic.
The Phoenician sea-traders, in the second millennium BC, provided the first means for distribution of amber throughout the known world. The Etruscans also dealt in amber until the spread of the Roman Empire ended their activities. As the overland trade routes were established, places of Baltic amber, light in weight and in value equal to gold, were carried as far as Byzantium and North Africa. Amber was prized both for its beauty as jewellery and its purported efficacy as a talisman for good luck, good health and protection from evil spirits in later centuries. It was also shaped into jewellery caskets and boxes, candelabra, urns, rosaries and all kinds of decorative pieces.
Today amber is still used as jewellery but only about 15% of that mined is considered to be gem quality. Much of that amber which fails to meet the jewellery standards for colour and clarity can be brought up to that grade by the process of clarification. Turbid amber, containing minute air pockets is slowly heated in an oil of the same refractive index. Refinement starts on the surface and works its way inward as the oil gradually replaces the air. The colour of the amber can be deepened or even changed if dye is added to the oil. Pulverised amber has long been used in the making of varnish and this coating is considered especially desirable form violins. The Soviet Union is experimenting with clear amber in laser research, unfortunately, details of these experiments are not available.
The primary scientific employment of amber today is as a "Golden Window on the Pasi". As the sticky sap oozed from the trees, insects, plants and small animals were caught by it and preserved, some intact. Amber is the modern world's best resource for the study of the fossil remains from the Eocene period. This has only been fully appreciated in the last century and scientists should have the opportunity to examine this life from the past before these fascinating relics cease to be easily accessible.
Amberoid, Pressed or Reconstituted Amber
At a temperature of 170˚ to 190˚ natural amber softens and becomes malleable. Small and non-gem quality pieces can be fused in a vacuum under heavy pressure. The semi-solid resin extruded into cylinders of pressed or reconstituted amber in a mould, many of the faceted amber necklaces seen today are produced in this manner. The amber must be carefully cleaned before processing and any impurities filtered out to provide a truly clear end product. Additives are unnecessary although some items do blend in a small proportion of a synthetic resin to lend extra cohesion. In Germany amber producers are allowed by law to call the product "genuine amber" if it contains no more than 1% additive.
Pressed amber is actually stronger than natural because any minute fractures or flaws inherit in the material have been eliminated. It is slightly heavier, but refractive index is the same as that natural amber. Modern techniques have enabled the amberoid processors to include the enhancing "sun-spangle" inclusions which formerly were a sign of natural amber exclusions. These sun-spangles (also called fish scales, spores etc.) are enclosed air bubbles which have been forced by the heat and pressure to form iridescent discs.
Because of its unique appearance and great value amber has long been imitated by both natural and synthetic substances. The list of natural stand-ins should probably be heated by copal, which could be termed "baby amber". True copal is a semi-fossil resin excreted by various tropical and subtropical trees and its age can range from 25,000 to 1,000,000 years.
True copal is relatively rare, and many recent (or raw) resins taken from living or newly dead trees are confused with it. Copal is softer than amber, it melts more easily and it does not take a high gloss polish. Insects and floral debris are found in copal, but they are always specimens of extant species.
Chunks of Kauri gum from New Zealand and many other recent resins from trees all over the world are frequently sold as amber. Occasionally these gums are shaped into smokers accessories or carved into small ornaments. Since Kauri gum has the same density and refractive index as amber but melts at a lower temperature, it has been used as a filler to cover holes left when genuine amber has had modern insects inserted to increase its value.
The oldest of the plastic amber substitutes is celluloid. Invented in 1867 Celluloid is a thermoplastic, softening when heated and hardening again on cooling. The infant plastics industry quickly became an important producer of many things used in everyday life buttons and buckles, photographic film, false teeth and imitation amber.
Celluloid was unsatisfactory because of its flammability was followed in 1890 by the development of casein, a formaldehyde-based plastic whose other main component was milk protein extracted from cheese. One of the trade names used in marketing this product was Galalith milkstone. Again the world was provided with a new source for imitation amber.
Then most common of the early plastics masquerading as amber was Bakelite invented in 1909 during a search for a shellac substitute. Bakelite is easily moulded, hard to dissolve, thermosetting (keeping its shape when heated) and it's both non-flammable and inexpensive.
The Berbers, a nomadic people of North Africa, greatly prized the small quantity of Baltic amber which they had acquired from overland trade routes. The Venetians, noting this, copied the original Barber beads in Bakelite and sold them as amber. An occasional true amber bead will surface among the many plastic imitations to be found in the souks of North Africa.
Baltic amber beads were sent to West Africa during the 16th to 19th centuries in trade for African gold, ivory and slaves. The Africans developed a taste for amber and being unaware of its origin, were satisfied with the quantities of synthetic imitations which filled the gap left by the end if the amber supplied via the slave trade.
During the 1970s many different types of African amber appeared in the United States. These beads are usually large and opaque and range in colour from yellow to brown. Most are flattened ovals or barrel-shaped, but some are wedges and modified diamond shapes. These beads are frequently found in ethnic shops and fascinating tales are spun about their history. The beads may be old and leave interesting histories but unfortunately most of these stories are pure fiction and the African amber was pure plastic.
Bakelite of European manufacture was fashioned into strands of Moslem prayer or worry beads. These have been widely used in the Middle East and have found their way to the Asian steppes. The beads are usually barrel-shaped and a lovely red golden colour. They too are often sold in today's shops and boutiques as genuine amber.
The glowing red plastic, done in imitation of Romanian Cherry Amber (and there's some doubt about the existence of that!) was also made in China. The Chinese had long possessed beads and carvings of true Burmese and Baltic amber. The substance had symbolic significances for them, since pine trees were often equated with longevity and the Chinese word for amber translates into "soul of a tiger" typifying courage. Amber, highly prized by the upper classes was often certified in China, however, this was done more in the sense of "imitation as the sincerest form of flattery" rather than with an intent to deceive. As early as the 6th century A.D. warnings were issued about amber substitutes
Recent Chinese carvings have been done in clear red resin which is usually not amber but Bakelite-type plastic. Occasionally the Chinese combined softened amber with other substances, thereby making identification much more difficult. The early 20th century saw the manufacture of imitation amber snuff bottles in China, and these are often complete with pine needles, dirt and bugs. The resin from which these small carved bottles are made is sometimes known as "Chinese snuff-bottle plastic".
There is one type of amber substitute which is freely acknowledged as partly synthetic. This is the material known as "polybern", which is an amalgam of small pieces of natural amber in matrix of amber-coloured plastic. Polybern is used not only for jewellery but for vases and other larger objects.
A newer amber-with-plastic combination has recently entered the market and is being sold as reconstituted amber from Germany. Actually this material is over 95% synthetic, and the remainder is minute fragments of amber. Its appearance at first glance is remarkably similar to natural amber.
Also having a resemblance in varying degrees to natural amber are a group of recently introduced resins of the polyvinyl and polystyrene families. These materials frequently have sun spangles and glitter quite beautifully. Now that it is possible to induce these discs in both pressed amber and synthetic resins the problem of identification has been made more difficult. These newest synthetic substitutes are showing up at both wholesale and retail levels with increasing frequency. The materials can be very attractive and some closely resemble amber. They are described variously as plastic, reconstituted amber, or just plain amber.
It is frequently a challenge for experts to distinguish amber from some of the better plastic imitations, and the problem is worse for novices. It is also sometimes difficult to tell natural from reconstituted amber. In the following section we will describe some methods of testing which can be done without much trouble or expense.
Simple test for the Layman
Except for mass spectrography, no single test can positively identify amber. We suggest using at least two or three from the methods described below.
Visual identification is extremely subjective and open to error, there is true amber which doesn't look like amber, and some fakes are excellent simulations. Plastics may have mould marks which are rarely, if ever found on reconstituted amber. The facets on Bakelite beads stay well-defined, while faceted amber tends to become worn. Sun-spangles produced in plastic lack the radiating lines which fan out in the spangles in amber. A pocket magnifier is a useful tool.
Through the ages amber has been used as a touchstone. Because it is a poor heat conductor, amber feels warm, most plastics at first touch will feel cooler.
We have found that tests using salt water are fairy accurate in weeding out many plastics. In a solution of one tablespoon salt to eight ounces of water, amber will sink. If the proportion of salt to water is doubled (two tablespoons salt to eight ounces of water) amber will float. These tests will not guarantee that a substance is amber, but they will eliminate plastics with a much higher or lower specific gravity. Care should be taken that no air is trapped in the hole of a bead, which will increase its buoyancy. Of course the salt water test cannot be used when the article in question cannot be segregated from other materials.
A reliable sensory test for amber involves the use of red-hot needle which is applied quickly to an inconspicuous area of the specimen. Burned amber gives a pleasant piney smell which is unmistakable. Burned plastic has a harsh and acrid odour, differing from one type to another. Galalith will give off the smell of burned milk. The hot pin test should be used with care on the combination substitutes. it is possible to obtain a pine scent from one part of a specimen and an unpleasant chemical odour from another.
Denatured alcohol can be used to separate recent resins from amber. A drop of alcohol on the surface of Kauri gum, copal or other non-fossilized resin will cause stickiness almost immediately. On the other hand, amber will not be affected before the alcohol evaporates. Also recent resins melt or soften in boiling water whereas amber requires a temperature of at least 170C (338F).
It is well known that amber, like many other resins, can be electrostatically charged through friction and will act as a magnet to pick up small pieces of paper and the like (as will many of its imitators). What is not such common knowledge is the fact that upon continued application of friction the polarity of the specimen will be reversed and the bits of paper will be repelled. This magnetic magic is not true of the synthetic imitations.
Under polarised light the natural amber will show bands of rainbow along the stress lines. In pressed amber the effect is as though the rainbows were shattered and evenly dispersed. (A little practice with known specimens is recommended.) A primitive but effective polariscope can be assembled by a novice using two polarised lens and some cardboard.
Light refraction, a measurement of the change in the angle of a beam of light passed through a substance, can be helpful in eliminating some of amber's imitators. However, the Refractive index for some synthetic substances is the same as for amber, and the test cannot be considered conclusive. In addition, the refractometer is an expensive tool.
Mass spectography will provide accurate information about a specimen, but the instruments and expertise needed to perform this examination are not available to the layman.
Our aim is to share what we have learned about this fascinating gem and its imitators (we're the first to admit that in the past we've been fooled more that once!) and to aid others in determining the true from the false.