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Sun spangled inclusions in natural amber


#1

This is from the GIA, I will post the entire letter at the end of
this. “Your observations concerning so-called nasturtium leaves or
sun spangles are for all practical gemological purposes completely
correct.”

Do not take any of this personal, as it is not intended as such.
That you read something different is not surprising, however some of
what you read is hardly accurate. Never just assume anything posted
on the Internet is true, it may or may not be, not everything in
print is true, also. I did not take offence with the tone of your
post. I was put off a bit by the effort, time, and a reply takes. Not
believing me is one thing, arguing that a recognized authority(s) do
not know what they are talking about because someone said different
is another. If you can keep an open mind perhaps you will learn
something.

I will start with this first, you wrote “Heating it in oil. will
clarify it, but those round fractures (more commonly called “sun
spangles”) are a tell-tale sign that this has been done.”

I had thought that using the IGS (International Gem Society) as my
reference would be enough. This is the exact quote, “Another popular
type of inclusion are “star spangles.” These internal fractures
radiate from a central point. While quite attractive, most are human
induced.” (Meaning, not all are human induced.)

Some amber contains inclusions known as sun spangles, with the
appearance of nasturtium leaves, although most of this is seen in
treated amber." (Again, note; not all with this is treated.)

http://therossjewelrycompany.com/gemstone.cutter.atlanta.amber.html

One should pay particular attention to what is on the bottom of that
page, the above, “We are proud members of the following jewelry
industry organizations.” the reason is this, always take the word of
a recognized authority. That the statement that this inclusion is
always proof of treatment is in circulation is unfortunate, it is not
true. At the same time seeing this, one, unless otherwise known,
should assume it has in fact been treated, this would be correct most
always, as said.

You wrote, "Again in regards to blitsen, or sun spangled, "They
don’t really count as an “inclusion.” At the same time only one of
your reference links you used to say this disproved everything I
said, had any mention to this subject at all, they in fact called it
an inclusion. (There has been email between us, Dear Jake, Thank you
for sharing your knowledge about sun spangles in amber.)

While clear Baltic amber (even with "spangles") is preferred by
some to amber in its natural state (which is why the heating
process is done), I doubt that naturally clear amber would ever be
treated to produce the fractures - it would be vandalism, like
intentionally cracking a flawless gem.

If you had ever ordered amber (pre-cut) from a cutting house you
would never had made this statement, it is in fact commonly done, as
it is popular. On Baltic amber they will ask you what color (shade)
then if you want high or low dome on the cabochon, they next ask if
you want it blitzed.

You wrote, “I don’t believe that heat and pressure have much to do
with the formation of amber from tree resin.” This is the answer:

“The complete transition from resin to amber has to have two
additional factors present: heat and pressure. Heat and pressure may
support the process of polymerisation and turpene evaporation but
their full effect upon the formation of amber is not fully
understood.” http://www.gplatt.demon.co.uk/typesof.htm

Here is the result of the lack of the above. "Borneo amber is of
Middle Miocene age. Specimens that come from sandstone beds are dark
and undoubtedly true amber (no reaction with alcohol), however
specimens that come from clay beds of the same age are yellow and are
copal (react with alcohol). Clearly the kind of sediment is very
important in this process."
http://www.gplatt.demon.co.uk/transfor.htm

You wrote, "Quenching has no part in the process, " no again. I
wrote that I amused that quenching (in water) did this. As this was
unimportant to me I did not investigate, at the same time I would
have been willing to place a small wager that this was the case, then
again for all I knew for a certainly was some other liquid may have
been used. Therefore I did not state it as fact. Here is the answer.

“Blitzer: is the German name of artificially reflecting fissures,
which develop after ‘cooking clear’ the amber in oil, followed by
cooling in water.” The Amber Dictionary-
http://www.museum-albersdorf.de/BERNSTEN/LEXICON.HTM

This I do take offence at, as it was basically how your letter
started. “Unfortunately, most of what is written on amber comes from
old references; accurate when written as far as was known, few
consult later archeology findings.” this was taken out of context,
that is not honest. Most on the history of amber will state the
oldest found is in France, dating from the Neolithic, one written
later mentioned that in Cheddar England beads dating to 8,000 BC have
been found. However, read this. “Worked amber dating back to 11,000
BC has been found at archeological sites in England.” Again, “The
earliest evidence that amber was known about, mined, and worked with
in the Baltic Sea/Gdansk area dates from between 8000. (BC)” I have
an archeological report, separate from this, referring to "workshops"
dating from this period.

Below, is what I wrote to the GIA (edited) and the response.

First I do not know if this, your office, is the right place to
ask, I apologize now if this question should have been directed
elsewhere (to a different department).

Perhaps you could help clarify something. I wrote (to a list)
that, quoting Don Clark, president of the IGS (International Gem
Society), Another popular type of inclusion are "star spangles.“
These internal fractures radiate from a central point. While
quite attractive, most are human induced.” (Meaning, not all are
human induced.)…

I feel this is of some importance as there is so much mis and
dis-circulating on the Internet as truth regarding
gems in general, all of which is often repeated

Response:

Thank you for your e-mail to our President, Donna Baker, which
has been turned over to me for a response.

Amber and related younger fossil resins are one of my favorite
gem materials from a micro standpoint since they give us a unique
window on ecosystems from the ancient world and their fluid and
gaseous inclusions also allow us to examine aspects of climate
change when compared to air and atmospheric water samples
collected today.

Your observations concerning so-called nasturtium leaves or sun
spangles are for all practical gemological purposes completely
correct. As you probably know these inclusions develop in cloudy
amber during the heating stage of the clarification process where
countless minute bubbles migrate to the surface and escape their
host when the host is sufficiently softened. A slight vacuum can
help in this process if essentially clear treated amber is the
goal. In many cases however, totally clarified amber is not the
goal, since some feel that so-called nasturtium leaves or sun
spangles look natural, and add a natural aspect to the treated
material.

These treatment-induced features are nothing more than discoid
decrepitation halos, really no different in many respects from
that those that occasionally occur in peridot and feldspars, and
also in many heat-treated corundums.

During the clarification process many bubbles can coalesce into
one and then expand rapidly as pressure builds causing a rupture
in the form of a disk. As cooling takes place the disk shrinks
and wrinkles in a uniform manner producing the texture on the
inner walls that, to some observers, make it look like a natural
inclusion of organic origin.

A great deal of fraud has resulted, either because of complete
dishonesty, or through ignorance. Please note however that not
all discoid inclusions in amber are the result of treatment
(although, certainly the vast majority are). Most are obvious
indicators of treatment, but when only one or two discoid
features are present as inclusions a close microscopic
inspection of the host material is required.

Fluid inclusions (droplets of rain or dew) and complete
arthropods or insects or insect parts, as well as any botanical
inclusions do not survive the clarification process in any
recognizable form. If an amber specimen that contains a discoid
feature also contains any of these recognizable inclusions you
can be sure it has not been treated through a clarification
process. Note also that “nasturtium leaves or sun spangles” can
also be induced in plastic through a similar processing (see
Photoatlas of inclusions in Gemstones Volume 2 page 303), so the
presence of such inclusions does not even guarantee that the host
is amber.

I hope this has been of some help. If you have any additional
questions you can contact me through my e-mail address or by
phone at xxxxxxxxxxx.


#2

Hi,

The GIA response seems to match what Kurt Nassau wrote about it in
"Gemstone Enhancement" (1984).

The discoids form when the heattreatment, either in rapeseed oil or
without oil, is followed by a too fast cooling down (not quenching).

Alain