Turquoise Discoloration?

[linda newman]

Purchased a small Zuni-bear shaped light blue turquoise stone at a gem and
mineral show. I wear it on a chain around my neck. It has discolored to
the point that it looks more like jade than turquoise. A co-worker
suggests that turquoise is a very porous stone and is being discolored by
skin oils. If this is the case, is there any solution I can soak the stone
in to return it to its original condition?

Linda
lne...@lib.occ.cccd.edu

[John Miller]

Much turquoise is highly porous and is easily discolored by oils. I
don't think there is any effective way to restore the original color.
The best quality turquoise is less porous and less subject to
discoloration, although care should still be taken to avoid exposure
to possible discolorants.

"Stabilized" turquoise has been impregnated with wax or resin to help
prevent discoloration and sometimes to improve the color.

--
John Miller, Gemcutter/Graduate Gemologist/CNE
Gemology & Lapidary Pages -- http://www.tradeshop.com/gems/

[Sue Toorans]

I need help from someone who has used a pitch pot. I just worked my very
first piece using a pitch pot. The first time the metal (brass, if it matters)
went into the pot nothing, other than annealing, had been done to it. When it
came out of the pot it was covered in pitch that didn't want to come off with
a heat gun. THEN I remembered that one of my reference books said to coat the
pitch side of the metal lightly with oil. Fine. I did that. When I removed
the piece from the pot the second time it was covered in pitch that did not come
off with a heat gun. At this rate I'll run out of pitch. Is there a way to
get the work to come out of the pot clean or at least mostly so? I end up scraping
the pitch off with a dull, blunt table knife (now a pitch knife) and then cleaning
the rest off with acetone free nail polish remover. What am I doing wrong? What
is the right way?

Sue
sue...@oes.amdahl.com

[JOHN FISHER]

Sorry Linda,The tuquoise has absorbed oils and they cannot be
removed.However normally this just improves the stones appearance. Don't
try to soak it in anything, wear and enjoy.

jack
jfi...@itri.org

[gess...@delphi.com]

Sue Toorans <sue...@oes.amdahl.com> writes:

> I need help from someone who has used a pitch pot. I just worked my very
>first piece using a pitch pot. The first time the metal (brass, if it matters)
>went into the pot nothing, other than annealing, had been done to it. When it
>came out of the pot it was covered in pitch that didn't want to come off with
>a heat gun. THEN I remembered that one of my reference books said to coat the
>pitch side of the metal lightly with oil. Fine. I did that. When I removed
>the piece from the pot the second time it was covered in pitch that did not come
>off with a heat gun. At this rate I'll run out of pitch. Is there a way to
>get the work to come out of the pot clean or at least mostly so? I end up scraping
>the pitch off with a dull, blunt table knife (now a pitch knife) and then cleaning

There is a very good new book on the market called CHASING, by
Marcia Lewis. Her suggestion for what you are experiencing is on page 33.
She suggests that the metal is removed by using a sharp small torch flame
to heat just one edge just enough to get a grip on the part with pliers.
Continue to lift gently with pliers while putting that little torch flame
back on the metal for one second at a time until the metal pops off the
pitch. She says there should be very little residue this way. Any remaining
residue can either be wiped off the metal with soft tissue (while metal is
still warm, or rewarm the metal to do this). Also remaining hard to reach
pitch can be removed with mineral oil wiped on the warm metal.

Hope this helps. If you're chasing, the book is an excellent one
to have for reference.

Elaine Corwin
GESSWEIN
elai...@aol.com

[Andrew Werby]

>Sue Toorans <sue...@oes.amdahl.com> writes:
Is there a way to
>>get the work to come out of the pot clean or at least mostly so? I end up scraping
>>the pitch off with a dull, blunt table knife (now a pitch knife) and then cleaning
>

[If residues of pitch remain despite your best efforts, try some of the
new citrus-based (terpene) solvents available as tar-removers at
roofer's supply stores. They are less toxic than the alternatives,
smell better (like orange peel), and work well.]

Andrew Werby - United Artworks

[The Registry, Ltd.]

linda newman wrote:
>
> Purchased a small Zuni-bear shaped light blue turquoise stone at a gem and
> mineral show. I wear it on a chain around my neck. It has discolored to
> the point that it looks more like jade than turquoise. A co-worker
> suggests that turquoise is a very porous stone and is being discolored by
> skin oils. If this is the case, is there any solution I can soak the stone
> in to return it to its original condition?
>

> Linda
> lne...@lib.occ.cccd.edu
Linda,
The discoloration of your turquoise is more likely to the natural
dehydration that occurs in turquoise that has not been wax or resin
impregnated. In addition, turquoise is colored primarily with
copper, which has a tendency to oxidize when exposed to the air.
The combination of the two factors above will result in a gradual
change to green. While many solvents have been recommended to
restore the blue color, repolishing is the only sure way to bring it
back.
Douglas K.Hucker

[C. M. Fox]

In article <hlOoZsH....@delphi.com>, gess...@delphi.com wrote:

> Sue Toorans <sue...@oes.amdahl.com> writes:
>
> > I need help from someone who has used a pitch pot. I just worked my very
> >first piece using a pitch pot. The first time the metal (brass, if it
matters)
> >went into the pot nothing, other than annealing, had been done to it.
When it
> >came out of the pot it was covered in pitch that didn't want to come off with
> >a heat gun.

I run water on my piece before I set it in the pitch pot. That way it
doesn't seem to stick as much. I also try to pull it out "cold" Ie: i
don't heat it with a torch. This also helps.

Carla