Restoring malachite

How can I restore the polished finish to a piece of malachite that
has lost its gloss completely and is now dull and flat? Thank you Pat

Pat -

The most effective way to repolish malachite is ZAM on a flat, hard
leather lap. As a surrogate you can use a piece of a thick leather
belt, using the back side of the belt where it is rough. Rub in some
ZAM on the rough leather, and gently strop the malachite stone back
and forth. It will take quite a while to repolish a stone which has a
totally matte surface, but it will work.

Jim Small
Small Wonders Lapidary

Dear Pat,

In my experience, as long as the Malachite is not too soft and
porous, Zam on a treated yellow buff is effective and quick. There
are other ways but it requires some lapidary equipment and is more
time consuming.

Thackeray Taylor
Rio Grande Technical Support

Hi Pat

It’s best if you can take the stone out of the setting. Depending on
the depth of the scratches go over the stone lightly with a
sandpaper “file” - I’d use 1,200 grit wet-or-dry silicon carbide
paper glued onto a 12" length of wooden yardstick or similar. If
it’s very abraded you might want to start with 800 grit. Do this
wet. Check often, drying the stone first (you can’t see scratches on
a wet stone). Use light strokes so as not to sand flat spots on the
stone. You can go to polish directly from 1200 grit. Or you might
want to give the stone a final touch with 2000 grit wet-or-dry paper
before polishing.

Then polish. I use 14,000 diamond past on a hard felt wheel for just
about everything, but be aware of the heat buildup. Use a light
touch. You can do the polishing by hand also by making another
yardstick sanding “file” but glueing leather onto it. Apply any of
the usual polish compounts to the leather - cerium oxide, aluminum
oxide, tin oxide, 14,000 diamond. For all except the diamond polish

Hope that helps,
Hans Durstling

1 Like

Though I have not personally worked on malachite I did have a pro
recommend Zam for polishing malachite. I would ruff it slightly and
then smooth it again and try the Zam.

my thoughts

Hi Pat By buffing my jewellery with Zam on a Chemkote buff I have
found many pieces of turquoise and malachite, being rather soft
stones, are also rebuffed as I polish a piece of jewellery with them
in it. Zam is also a greenish colour that is similar to the colour of
the stones.

Karen Bahr “the Rocklady” (@Rocklady)
K.I.S. Creations
May your gems always sparkle.

Use ZAM on a muslin buff, or if you have an old treaded yellow buff
that will work to, just don’t ride the buff to hard let the ZAM do
the work

Kenneth Ferrell

Pat, the standard for polishing malachite is ZAM on an stitched
cotton buff (not the yellow wheel but the plain cotton). I don’t know
how large the piece is you are referring to but I have repolished
malachite boxes up to 8X10" with outstanding results. Just be sure
to keep a good grip on the piece and do not use too much pressure.
The wheel will tend to want to rip the piece from you hands first
off, and if you use too much pressure you could end up with buffing
grain in the surface. Nonetheless, this will do an excellent job.

Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry! @coralnut2