The Oban river quartz mine in Au. has been providing a light smokey
quartz rough that when cut on the “B” axis produces a reddish,
purplish hue for years. It is very abundant, and very cheap.
Calling it Red Amythest is just another way to push the pricing up
for quartz.
Hi Leonard,
This occurrence of amethyst, near Jackson’s Crossroad, GA has been
known for a long time, but a recent change in property ownership (
couple of years ago, I believe) has been accompanied by increased
mining and marketing.
The material itself is sometimes exceptional in color, although much
of it is somewhat pale or overly dark. Only cut material and mineral
specimens are being sold, but I believe that fee digging is still
allowed. The material I saw at Tucson last year was very high
priced, IMO, probably reflective of the high cost of mining, and I
did not se much material available. Personally, and I have not seen
ALL the material from either location, the Four Peaks is as nice or
nicer.
Basically, most South American material is often accompanied by a
slight smoky gray or brownish undertone. We are so accustomed to
seeing that material that when we see amethyst lacking the
undertone, it can be startling in its beauty. Among cutters, most
would agree that the best of the Uruguayan material easily matches
the GA or Four Peaks material, closely followed by some new, some
less saturated material from Bahia, Brazil and some scattered
deposits in Africa. Of course, fine material can be found in odd
places, so the above is a very general statement and others may wish
to throw out their own opinion. And beauty is in the eye of the
beholder.
Best regards!
Wayne Emery
The Gemcutter
"Bending Light Since 1975"
my understanding of the story from my friend who has cut some of the
GA amethyst material i mentioned some odd posts ago go like this.
amethyst deposit on private property - the owner is very prudent and
cautious - some word gets out - many years pass by - deal is struck
last year or so - no rough is allowed for sale at all - i will meet
with the supposed sole distributor next week to purchase and can post
more info @ that time. but for now to describe the material it is has
a highly saturated even color and it is not red but it has very
strong red undertones and it throws distinctive red color when the
facets reflect light and the quality of the quartz crystal is very
very clean and free from inclussions - later goo
Part of me believes it must be natural because of its apparent age and the other part believes it must be synthetic because it doesn't quite fit into anything that I can think of!
Apparent age is misleading, synthetic corundum has been around a
loooong time.
I don’t have the literature handy, tis Christmas afterall, but you
should be able to search, or maybe someone else here has the info
handy…but here’s what you can do w/o instruments.
syn corundum will often exhibit growth lines. They appear as curved
lines when backlit. Sometimes its helpful to hold a thin tissue
between the light source and the stone. Look at it from all angles.
You need to not confuse a curved line with this anomoly… A line
that extends under both bezel facets and table may at first glance
appear curved because of I dunno, a lensatic effect? optical
illusion? You may also see tiny bubbles or clusters of bubbles that
sometimes occur along the growth lines.
I don’t deal with this stuff often so my memory lapses on whether
syn corundum alexandrite-like material will always show this
property.
Based on my interpretation of the original description I’d bet money
it is indeed syn corundum. 20mm, only one tiny chip after all those
years.
“I got it at the mine in Alexandria, Egypt!” yuh.
Hi folks…
Try Siberian, many more hits and a better descriptions of the material are available. Leonid suggested the alternate name and he was correct, you won't find much under red amethyst.
I have two very tiny peices of what’s supposed to be Siberian
amethyst… Body color is what a dark amy should be… Under a
bright light I can see a red glint, I guess I would call it…
A few years back the Milwaukee Public Museum hosted a traveling
pearl exhibit…
There was this necklace from Victorian times (if I remember the
display card correctly) that of course had pearls, but what stopped
me in my tracks, was that the amethyst showed red and blue
glints…almost like dispersion…? There was a cluster of
halogen
type (?) lights above the display… These were huge faceted
stones…18X13 +…
I said to meself…“It can’t be…” But according to the provenance
card… Was Siberian Amethyst…
Absolutely gorgeous…
Gary W. Bourbonais
A.J.P. (GIA)
Try Siberian, many more hits and a better descriptions of the material are available.
As I said in another post on this, without seeing the stone
everybody’s just guessing - including me. But I did look at Siberian
amethyst - found a couple of vintage pieces, among others. Very
lovely, very nice, but alas, it is amethyst. To call what I saw “red”
is to be color blind - just what I saw. The stone Jo-Ann has is more
like Harriet’s original description - truly reddish purple, and not
amethyst-ine at all. It’s a unique color - maybe you could call it
some sort of “plum”, as there are many plums… Hers is also
obviously sapphire if you look at the lustre, cutting, refraction and
all that. Plus we had it looked at to know really what it was -
natural, etc. But having not seen Harriet’s stone, it’s just mental
gymnastics, ultimately. Fun…
Harriet - here’s a good link to Wikipedia about synthetics:
This is one of those topics that we all find interesting if not
fascinating, but of course without seeing the stone we’re all just
guessing - me, too. To me what’s going to tell you right off whether
it’s quartz or sapphire is the lustre - quartz looks like glass and
sapphire has a sheen to it that’s unique. One other telling thing is
that if it really is that old, as you say, if it was worn at all an
amethyst would be really beat up, unless it has been recut - sapphire
will last much, much longer. Seeing it is the key, though. It could
be something entirely different than anybody here thinks - some
stray, arcane stone that some lapidary found years ago. There’s no
telling without actually seeing it.
I’m probably way off mark here (as I often am) but the only reddish
purple stone I can recall is rhodolite or almandine garnet? Could it
be a very good, more purple whilst still definitely red example of
one of those?
Helen
UK
a highly saturated even color and it is not red but it has very strong red undertones and it throws distinctive red color when the facets reflect light and the quality
Thank you Goo,
Your description is right on. Pleochroism of amethyst is from
reddish- violet to bluish-violet. With proper orientation gem should
exhibit these red reflection. Wouldn’t mind getting my hands on some
of it.
Leonid Surpin.
There is no gemological test which would definitely separate natural amethyst from lab-grown. Sometimes, if amethyst has characteristic inclusions which can be linked to a particular geographical location, than maybe. But it is far above the ability of the run of mill appraiser. However, since amethysts are generally clean, it is a remote possibility. You need to find a gemologist with a lot of experience in amethysts which is probably rarer than the stone itself.
Leonid - Not sure gemmological laboratories would appreciate your
first sentence. There are ways to test natural v. synthetic
amethyst. Not always easy granted, but inclusions in some stones
(nail-heads, colour zoning, Brazil-law twinning and ultimately FTIR
spectrometery will usually get most these days. Worth checking out
amethyst + FTIR on some searches and in some gemmological journals.
Stefanos Karampelas a Phd student at Nantes university has also done
some excellent work on this very subject.
Not sure gemmological laboratories would appreciate your first sentence. There are ways to test natural v. synthetic amethyst. Not always easy granted, but inclusions in some stones (nail-heads, colour zoning, Brazil-law twinning and ultimately FTIR spectrometery will usually get most these days.
Yes, there are ways, but Amethyst presents a special problem.
Inclusions do not help unless they are present. Amethyst is
frequently clear and we really perfected quartz synthesis so
synthetic crystals do not have tell-tale signs. Brazil-law twinning
worked for a while, but now twinned crystals easily synthesized, so
it is not a proof anymore. Since amethyst colour is naturally
radiation induced and natural and synthetic gems are virtually
identical it is impractical ( while theoretically possible ) to use
sophisticated testing due to high cost of testing and relatively low
cost of amethyst. This is exactly why when Brazil-law was no longer a
conclusive test, the price of the Amethyst collapsed. The gem would
cost much more is identification was commercially feasible.
There are indication that one can use but the interpretations are
subjective and depend on individual colour perception. Difference in
pleochroism colour range exist, and colour distribution in natural
amethyst is differs from synthetics. In natural amethyst colour is
restricted to grows zones associated with rhombohedral facets. Grows
zones associated with pyramidal facets are colour free and have
different degrees of transparency. If crystal is twinned, ( and most
of them are ) the colour scheme is even more complex. Synthetics do
not exhibit such colour distribution, but it is not easily detected
and therefore is of little practical value.
Leonid Surpin.
Hi there
I have just spoken to the customer who owns the ring and she will be
able to pop the ring back to me some time soon and will be very
happy to have me photograph it so that I can show you all the stone!
When I have it I’ll post it on my blog or somewhere like that and
mail the link to you to see what you think.
Interesting point about the difficulty about finding somebody expert
in natural vs synthetic amethyst and I’ll be sure to take it
somewhere that I feel confident they will be able to advise. I will
see if I can persuade the customer to let my colleague take it up to
the Gem-A in London for their opinion as she is currently studying
there. I had never thought that people would bother to make synthetic
amethyst as I would have thought that the lab costs would have far
outweighed the cost of a new piece - but I guess that is for the
standard purple quartz - and maybe there is a point in doing this for
an unusual stone like this. Who knows. I still feel like it is a
natural stone.
The customer was telling me that she picked it up from a funny
little junk/antique shop for about 200 GBP (about $400USD) and this
is the same junk shop from which she recently bought an absolutely
amazing art deco opal and diamond pendant for less than GBP 2000
which I valued at over GBP 12000. I think I need to find out where it
is and go along to this shop! As I was saying the stone I have been
asking about which may or may not be a red amethyst is large so
either way and whatever the stone turns out to be I think that for
GBP 200 she has a bargain…it is certainly 18ct yellow gold and of
interesting construction too so it will be interesting to see what
comments you have about the mount itself too as I have always found
that the mount says so much about the stone in this sort of piece.
Thanks for the continuing posts - I am finding them very interesting
and educational.
Very best wishes
Harriet (UK).
Harriet,
If you will contact TimFinucane @yahoo.com.au he is a gemologist
that lives about 60 miles from the mine that produces "Red Citrine"
that comes from the Oban. This material also has purple hues.
Jim
Hi Harriet,
IMO, a picture of your material would not be very revealing. Color
and saturation are only a slight clue to identity, and good
gemologists have learned to trust their instruments before their
eyes in many cases.
Because the luster and RI of amethyst is so different from the
synthetic (or natural) corundums mentioned, however, a simple glance
would differentiate the two.
Any jeweler with entry level tools (refractometer) would quickly be
able to differentiate these materials.
Also, while lab grown quartz is available for under US$100/kilo in
the rough grown crystal form, finer amethyst that ALMOST looks as
good as some of the grown material, and has a MUCH higher cutting
loss factor due to inclusions, banding and proper cutting
orientation can easily cost $1500 -2000/kilo. Or did LAST year! The
falling dollar will add 30-40% to that cost this year here. I
regularly sell custom cut high end natural quartz for $50-60 per
carat and it is a bargain at that price. Fine natural material is
not easy to find and it can be stunning. Four Peaks material with
mediocre (my opinion) cutting is often seen at $75/c and more.
You said that “the mount says so much about the stone…”. Could you
explain. Here it is not unusual to see synthetics in expensive
mountings, and many if not most, of the small sapphire we see in Art
Deco platinum pieces we synthetic, as well. IOW, it is not prudent
to make guess about the stone based on the mounting, but perhaps you
meant something else?
Wayne