There's a lot of misabout amber and copal. I can't
straighten it all out because I'm not an expert, but I have studied
it a bit.
The whole amber process began as a tree sap from an ancient wood.
I'm sorry I don't remember the genus name. The exact age varies, but
is certainly in the millions of years. At first its molecular
structure was a monomer when it was sap or resin. It then went
through a molecular change over a great deal of time, probably
through compression and probably with some heat, and became a
polymer. At that point it was copal. When it's copal it still has a
great deal of volatiles in it and I believe it has a fairly loose
structure. The volatiles are essentially a kind of natural petroleum
derivative. Amber and copal are sort of like a naturally forming
plastic. After all, petroleum, from which plastic is made, was
formed from organic plant material too.
It seems to have depended on the specific location and surrounding
conditions as to how long it took for the volatiles to escape and
for the transformation from resin to copal to amber to take. In some
places, over a great deal more time, the volatiles continued to
escape causing the copal to compact more and turn into amber.
Actually, it seems that amber still continues to change because
amber that has been out of the ground for a long time, even in the
hundred year range has gotten harder and some believe that red amber
comes from yellow amber's exposure to air. Amber also seems to get
more brittle as it ages in the air so lots of Victorian amber
jewelry is dark red easily broken. As I understand it copal from
Columbia may be as old as 100,000 years. If it's still resinous and
sticky, it's very young, like 10,000. Copal tends to be extremely
brittle and will chip or break easily. I understand that old copal
can, in fact, take a polish. But personally I haven't messed with
it. Amber from the Dominican Republic, the second most plentiful
source can be as young as around 20 million years old and up to
about 45mil, though please don't quote me on those time frames.
Baltic amber, the most plentiful source, can also be as young as
about 30mil and as old as about 60mil. even 70. Not sure about
Mexican. Amber from New Jersey and Myanmar, formerly Burma, can be
even older and I think is about the oldest on earth. There are other
sources of amber but not in profusion.
True green amber comes only from the Dominican Republic, and Chiapas
in Mexico although I've seen some Baltic white amber that also has
some green coloration in it. It's not exactly clear what causes the
green in Dominican except that there seems to have been quite a bit
of heat involved. In the DR It also tends to be found in a blue gray
sandstone layer. There is also blue amber from the Dominican
Republic. As far as I know that's the only source of blue. The cause
of the color in that is unclear except that it also seems to have
been subjected to heat and comes from the same sandstone layer. Blue
and green amber from the Dominican Republic are very, very rare and
new supplies have shrunk even more in the last couple of years.
I've read that Green is about 2 tenths of one % of the world
production and blue is about 1 tenth. But that was before the source
dried up. I was told a couple of months ago by a man who was in the
DR looking for amber that there is less than one lb a month of blue
and green from the DR being mined now. So the price of these has
risen sharply. I was fortunate enough to have spent the winter in
the Dominican Republic two years ago and bought quite a bit of amber
including blue and green. I've got some very rare stuff. It's very
unusual to find fossils in blue and green amber. Most that are found
are completely desiccated. Yet I even managed to get one green piece
with a very well preserved fossil in it, a fungus gnat. If anyone
wants to see a startling photo of it that I took with my microscope
and a digital camera, email me.
One more thing about the commercial green amber. Most of it is
Baltic that has been dyed on the back. Hope this explanation was
worth your while.