Maggie Campbell Pendersen was insightful and informative in her discussion November 18th on Amber.
Amber is fossilized tree resin (not sap), which has been appreciated for its color and natural organic beauty since Neolithic times.
Amber is used as an ingredient in folk medicine, as jewelry, and in art.
The 17th century was the Golden Age for Amber use in art and carving, often combined with Ivory.
The process by which plant resin matures to become ‘amber’ is through a gradual transition over millions of years, from liquid Tree Resin, to a dried out solid stone, without any abrupt changes. The youngest Amber has been dated to 12 Milllion Years, while the oldest may be up to 300 Million Years old.
There is no dividing line or specific age at which we can definitely say that the resin became amber.
Young resins (copal) are less stable than older ones (amber). The process of polymerisation is incomplete in copal, volatiles are still evaporating, and the material is, in effect, still drying out.
This causes the surface to shrink and subsequently flake away.
Copal is also more susceptible than mature amber to excessive heat or solvents.
There are a few rules of thumb that we can use when buying “Natural” Amber. Color:
Natural Amber occurs in colors ranging from pale honey to dark brown, and some can be transparent or opaque.
Natural BLUE Amber does not exist. Amber may have a blue tinge to it when viewed in light containing ultra violet rays (e.g. sunlight), as it can fluoresce giving a blue color. This is especially true of some amber from the Dominican Republic, Mexico and Myanmar.
Natural RED amber does exist, but it is extremely rare, and the natural color is a slightly rusty red. The amber found in Myanmar, called ‘burmite’ is 100 million years old and occurs in colors that range from clear golden thru red to very dark brown. It is only mined occasionally and in very small quantities, so the chances of coming across it are remote.
Natural GREEN Amber does not exist, any material on the market that appears green has been subjected to some kind of treatment.
Baltic amber is the most common, making up 98% of the market, it is treated in many ways, one of them being to heat the back of a piece till it is burnt, This makes the amber look green, when
viewed from the top/front. From the side it will be the natural color. The same effect can be produced by backing the amber with black material, usually plastic.
Some, Dominican and Mexican ambers can fluoresce and look green in the right light, but the amber is in fact golden. A new process has recently been developed which does turn amber green.
But it must be emphasized that the resulting ‘green amber’ is not natural. Additionally, most of it is produced from imature copal, which may only be 300 years old.
The long-term stability of this relatively new material is, as yet, not known. The general public is under the impression that ‘amber’ is millions of years old. To sell a material that is only 300 years old (and may not be stable), as ‘amber’, seems to most gemmologists to be misleading.
Small fragments or powders, formerly thrown away or used only for varnish, are now used on a large scale in the formation of “amberoid” or “pressed amber”. The pieces are carefully heated and then compressed into a uniform mass by intense hydraulic pressure. The softened amber is then forced through holes in a metal plate. The product is extensively used for the production of cheap jewelry.
Often amber (particularly with insect inclusions) is counterfeited using a plastic resin. A simple test consists of floating the piece in heavily salted water, where amber will float most heavier plastics will sink.
Additionally, counterfeits will often have a large insect with too-perfect a pose and position of the trapped insect.
This may be all you need to know about amber, but should you wish to learn more about it, and the treatments and imitations on the market today visit: http://maggiecp.com and sign up for her Organic Gems On-line information center.
A Special Happy Birthday to Bobby Mann – DCGIA Chapter President !
50/50 Raffle Winner !
Meeting Summary by: Charlie Marts
Photos by: Theresa McGowan – Bobby Mann & Maggie Campbell Pendersen