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Chatoyant Beryl


#1

Just bought a large Chatoyant Beryl crystal in the color that I call
seafoam, a blue/green. It has good saturation and the stuff
practically glows in the dark. I’m wondering how many metalsmiths
out there would use this material if it’s clean with obvious
chatoyancy. I was able to cut a 16 carat cab and expect there to be
others.

Also, would anyone know whether heat will make this bluer and what
the specs are for heating?

Derek Levin


#2

Derek, I am a lapidary and stone carver and would love to have a
small piece of this stone. I have a deep blue boulder opal that is
getting waves carved into it because I had to eliminate some cracks
(caused by the miner hitting the stone with a hammer to see what was
inside a piece of ironstone). The piece is crying out for a carved
dolphin to jump out of the waves. I need a piece about 10mm long and
maybe 5 or 6mm wide preferably with the chatoyancy being lengthwise
to the piece. If you have such a piece left over after your cabbing
please let me know.

@r_carew
Thanks & g’day
Rick Carew


#3

Chatoyant beryl (a.k.a. cat’s-eye aquamarine when it is blue-green
in colour) is not particularly well-known, but it is quite
sought-after as a collector’s item. In addition, because the name
"aquamarine" has such good name recognition, I would think that it
might well appeal to the discerning ordinary consumer as well as the
collector. It can be very attractive, although the cat’s-eye effect
isn’t as fine as in chrysoberyl.

    Also, would anyone know whether heat will make this bluer and
what the specs are for heating? 
I've never actually heat-treated any myself, but I've read a little

about the heat-treatment of ordinary aquamarine. Heating blue-green
beryls usually results in the green tones fading, leaving the blue
behind. I believe that the required temperature range starts at
about 650 degrees centigrade, although I know that hotter
temperatures are also used. N.B. if you overheat beryl it will
eventually decompose into a type of glass, becoming opaque and
unattractive in the process.

However, there is a general principle in gemstone treatment that

says that it is advisable to only heat-treat the cleaner, more
flawless stones. If you heat-treat a stone with many inclusions, you
are more likely to end up with breakages. Chatoyancy in beryl is
normally due to many inclusions: fine, parallel growth tubes that run
along the c-axis of the crystal. These growth tubes might lead to an
increased risk of the stone fracturing when you heat it. However, I
do know that beryl has a pretty low coefficient of thermal expansion,
so in theory this might mean that the risk of fracturing is slightly
lower than for some other gemstones (particularly at the
comparatively low temperatures required for beryl). If you do
decide to heat-treat it, you might want to ensure that the
temperature rise is slow and gradual, and that the stone is not
cooled down too quickly afterwards. But you should probably consult
an expert on gem heating first!

The stone sounds interesting - may I ask where you got it? 

?8-)
-Michael.

#4

Yes , its there and I stock them . usually the cats eye are faint
and the stone will be smoky or filled with inclutions ( thats what
gives the eye in the first place ) No heat treatment would not
enhance the blue But will dilute it ( i presume you need to treat it
with radiation to improve color )

Ahmed shareek
http://www.ahmeds.com/shop


#5

A new question about chatoyant beryl. Is anyone on orchid familiar
with a blue chatoyant beryl with practically no green? I just got a
small chunk but have been unable to find references to that specific
color.

Derek Levin


#6

Derek,

I have at least a kilo of chatoyant blue and different pastel shades
of beryl from Brazil. These were purchased during the early 1980’s
in Tucson. I have cut about 20 or so stones from these parcels and
put them aside because none that I cut were what I would consider gem
quality. Each crystal looks good in the rough, but when cut are a
little too murky or off color.

Chatoyancy can occur in any gemstone. Last year I saw a beautiful
cat’s-eye tanzanite. It had one of the sharpest eyes I have ever
seen and it was priced way out of my range.

Gerry Galarneau Any one who is a show dealer or jewelry maker who
makes their own products and wants to correspond with me off ORCHID
please do so at @Gerry


#7

Dear Derek First is it a blue like sapphire blue or like aqua blue?
second all beryl with the possible exceptions of Bixbite and
Goshenite( I’ve never heard about catseye Bixbite but probably
couldn’t afford it if it did exist!!!) has chatoyant examples. For a
definitive answer contact the GIA and pay for an appraisal…but
don’t be supprised if it turns out to be a treated form of Aqua
catseye ( again something I’ve never heard of but that doesn’t make
it not the case) Good luck and if it turns out to be something new
and you cut it Please keep me in mind for one of the stones!!! as I
just put the new red " beryl " and a heliodore into my collection of
catseyes and starred stones and would like the chance to add this to
them. HTH Ron


#8
a blue chatoyant beryl with practically no green? 

The chatoyancy in beryl is caused by fine growth tubes, and I’ve
seen stones or photographs of stones that show the effect in
colourless (goshenite), blue and blue-green (aquamarine), pale green
(green beryl), deep green (emerald), and deep pink (morganite).

That really only leaves the yellowish tones (heliodor) and red - and
I don’t know of any chemical reason why these colours shouldn’t show
the effect as well.

?:sunglasses:
-Michael.


#9
 That really only leaves the yellowish tones (heliodor) and red -
and I don't know of any chemical reason why these colours shouldn't
show the effect as well. 

Oops, I forgot deep blue Maxixe-type beryl. Never heard or seen of
a cat’s-eye stone in that variety either.

?:sunglasses:
-Michael.