Never tried this before, but going by what Paul said about bakeing a
Cypraea, I put a Cypraea milaris in the oven at 300 degrees and on and off
for about a week now it has been settin in there doing nothing much.  the
color has changed a little, but the spots still show well, so eburnea must
be the albino form of milaris not a baked form.  Paul did not say eburnea
was a baked milaris, only that they looked the same, but mine did not turn
white.  So back to work, been on this thing long enought for one time.  John
-----Original Message-----
From: [log in to unmask] <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Thursday, November 25, 1999 10:09 PM
Subject: Re: Baking cowries


>Yes, dark-colored shells (not just cowries) can be changed into "golden
>forms" or "red forms" by baking for 30 minutes at 300 degrees Farenheit.
>Also, a light-colored shell can be changed into an "albinistic" specimen by
>the same process.  The reason is that many shell pigments are not heat
>stable, and break down into uncolored substances or differently-colored
>substances when exposed to substantial heat.  I did a bit of experimenting
>with this a few years back, after I read some reference to it.  In a light
>colored shell like Conus textile, Cypraea miliaris, or Oliva reticularis,
the
>pigmentation may be completely destroyed, resulting in a pure white shell.
>This can be a problem because, for example, Cypraea eburnea is essentially
a
>white Cypraea miliaris; and Oliva olorinella is a white Oliva reticularis.
>Such white specimens usually have higher commercial value than the
>"normal-colored" specimens.  In a dark shell like Conus marmoreus (white
>tents on a nearly black ground color), the pigments are not usually
>completely destroyed by heating.  Such a shell may come out with a reddish
>ground color, the white tents remaining unchanged.  Interesting, since I
have
>occasionally seen "red form" Conus marmoreus offered, at high prices.  The
>idea of looking for fine crackling caused by the heat may be useful for
>highly glossy shells like cowries and olives, but not for a murex, volute,
>cone, etc.  And, with sufficient care, such cracking can be largely avoided
>even in cowries and olives.  I found that two elements were most critical -
>changing the temperature gradually, and avoiding direct contact of the
shell
>with hot metal.  The first consideration was addressed by placing the shell
>in a room temperature ove before opening the door.  I addressed the second
>issue by placing the shell in a glass (Pyrex, Kimax, or Corning Ware) dish,
>which worked quite well, or on an asbestos pad, which worked best.  I
really
>don't know if anyone has attempted to pass off as genuine shells altered in
>this way.  But I am taking a closer look at albinistic and other unusually
>colored specimens before I lay out any money for them.  One albinistic
shell
>may be worth a hundred times as much as a normal colored specimen.
Therefore
>a dishonest person could theoretically make many attempts to get a good
>looking fake, and still make a tidy profit if he produced a single passable
>specimen.
>Paul M.
>