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Backing Moonstone Cabs


I was looking for a show of hands on the best way to set and show off
small moonstone cabs. Mylar? Prism tape? Black or silver backing?

For those of you who use foil, how do you attach it to the cab? I was
looking for some double-sided sticky Mylar tape, but was unable to
locate such a product. I did find some interesting prism tape that’s
used to decorate riffle butts for band competitions, but it only has
the sticky back on the reverse side.

I was looking to set some smaller 4-6 mm cabs into wide band sterling
silver ring. I have both white and peach moonstone. I also wanted to
avoid a open backs so I wouldn’t have to mess with creating seats for
such small stones.

Tracy’s Treasures

I’ve used a trick to make moonstone look like a hologram. Get some
black antique solution and apply a small coat to the bottom of the
seat. After it dries put a small dab of epoxy on top of the antique
solution and insert the cabachon. Wait about 1/2 hour and then gently
burnish the sides of the metal over the stone. You will be amazed at
how great it looks !

Margie Mersky - Wax Models & Miniature Sculptures

  I was looking for a show of hands on the best way to set and
show off small moonstone cabs. Mylar? Prism tape? Black or silver

Dear Tracy and All,

I know this question has popped up occasionally so I would like to
share a great tip I learned form a wonderful jeweler and teacher.
His name is Phil Poirier. If you ever get an opportunity take one of
his work shops I highly recommend it! Any way, to back a transparent
cab use stainless steel foil found at most machinist suppliers. Once
polished it is highly reflective and will resist tarnish for many
many years.


Thackeray Taylor
Rio Grande Technical Support

Hi Tracy,

I frequently back various kinds of stones with regular household
aluminum foil. I use super glue (cyanoacrylate) to secure the stones
to the foil and cut around them with an Exacto knife. I’m thinking
of switching to Mylar, though, because the aluminum foil has a slight
grain which shows slightly under transparent

As for black vs. silver for moonstone, that’s a matter of taste.
Most moonstone dealers show their stones on black velvet, which
should tell you something. However, I usually prefer the look of
gold or silver glowing through from behind them.



My friends Judy and Anne taught me to paint the bezel bottom with
black fingernail polish to show off moonstones and the lighter blue
chalcedonys. It works a treat!

Talisman Design

Tracy, you might find my method effective for backing translucent
cabs. Because I have a gilding background, it was natural for me to
paint a very thin coat of 1 or 2 - hour gold size on the flat back
of the cab. This size is a clear, colourless varnish used in applying
metal leaf to glass or polished gesso, and is easily obtained from
gilding suppliers. After the stated amount of time on the bottle (I
tend to use the 1 or 2 hour version - the longer versions, for
example 24 hour gold size, give a slightly better finish) you will
find that the varnish on the back of the cab is virtually dry with
just a slight ‘tack’. This is the time to apply metal leaf, for
example silver, aluminium or gold, to the back of the cab. I choose
silver under moonstone, and gold under some garnets. Just press the
leaf on gently with a pad of cotton wool. If you leave it for another
24 hours you can gently burnish the leaf, but often the effect is not
very noticeable.

Finally, if you used silver leaf, you MUST apply a coat of
tarnish-resistant varnish or paint (e.g. Lascaux) to the exposed
back of the leaf. You will however find that in most instances
aluminium leaf is just as good, and doesn’t usually require sealing
against tarnish; although my natural instinct would be to seal it
anyway in case the cab is later subjected to chemical cleaning
treatments.I have experimented with various metal foils and prism
tape, but generally found them disappointing. Also, I would worry
about their wear characteristics, especially with regard to fading of
foil colours.

Paul Jelley