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Final polish on Chryscolla-Malachite


#1

I just did my first gemstone cutting on Chryscolla-Malachite and
would like to know the best method for getting a good final polish. I
used cerium oxide, but I’m just not happy with the results. I had
purchased some C-M cut stones a few years back and did this recutting
to make matching earrings for a pendant. I’m not getting the same
degree of polish that are on the purchased stones. Any advicee

Thanks,
Bonnie Cooper


#2

actually, the best thing you can do with any of the soft stones in
the copper family is to take it over to your jewelry buffer and use
a buff with Fabuluster or Zam…it will give it a nice shine. I find
that trying to polish it on cerium oxide with a felt pad tends to
make it undercut at times. Otherwise, I’ve been told to try chrome
oxide for green stones/malachite.

Jeanne
jeannius.com
creativecabs.com


#3

Hello Bonnie,

First time with Chrsocolla/Malachite or first stone? This could be
problematic if the latter and a bit tricky if the former.

The green bits are softer than the blue bits and will undercut and
orange peel with most oxides on soft laps. Old rockhounds swear that
using a variety of old worn out sanding discs and finishing with
Chrome Oxide is the key to success, a method I would rather swear
at. Chrome Oxide is filthy stuff and worn sanding discs are hardly
predictable.

My preferred method is using loose diamond grit for sanding and
polishing on Poly-pads. I have no trouble getting a mirror finish on
Jade, Lapis and other stones that are notorious for undercutting.

Tony.
Anthony Lloyd-Rees.
www.TheGemDoctor.com
Vancouver, Beautiful British Columbia


#4

I’ve been having really good results with a polishing powder that
came with my Inland Swaptop. It doesn’t say what the powder is, but
it has been great on everything. The key is to grind on a 14,000 grit
wheel twice or three times before going to the polish stage. Then the
polishing goes a lot faster without cutting into the stone.


#5

Depends on the chryscolla in my experience. The stuff comes in
varying degrees of hardness from nearly butter soft to gem silica
hard.

For the soft stuff, do as Jeanne suggests and buff it with Zam or
something similar. On the harder material I use diamond – usually
12,000 grit but sometimes higher.

RC


#6
actually, the best thing you can do with any of the soft stones in
the copper family is to take it over to your jewelry buffer and
use a buff with Fabuluster or Zam...it will give it a nice shine. 

Or, if you have proper lapidary equipment, polish with diamond
compound. That solves the problem some of these materials have with
orange peel or undercutting or the like…

Peter


#7
actually, the best thing you can do with any of the soft stones in
the copper family is to take it over to your jewelry buffer and use
a buff with Fabuluster or Zam...it will give it a nice shine. 

The best lapidary tip I got from a fellow lapidary who got an amazing
shine on the Sonoron Sunset, that hit the market a couple years ago
and is made up of a combination of copper mineral (cuprite,
malachite, etc.), was to let the stone dry out for a day or two
after grinding then hit it with Zam.

Rick Copeland
Silversmith and Lapidary Artisan
rockymountainwonders.com


#8

The traditional polish for malachite is tin oxide on leather. add a
drop of vinegar to your water and wash well afterwards. I have found
that 1 micron diamond [25000] works well on a silk cloth or you can
use colloidal silica on soft felt for crysocolla for good results.
you will neep to lap to 3 micron diamond paste with this first
though.

in short, there are many ways of getting a good result as long as
you have a good prepolish [at least 5000 grit SiC].

Nick


#9

I have had good success with a product called Zam on a coton buff.
This is done dry on a polishing arbor. Make sure that there is a very
good dust system, or wear a mask, as malachite can cause lots of
problems if the dust is inhaled. Better yet, just wear a god mask.

Good luck
Steve Ramsdell


#10
Better yet, just wear a god mask. 

OK, I know this is a typo and I’m guilty of numerous fat fingers a
day and Steve meant to say “good mask”. But this tickled my funny
bone. I’m thinking along the lines of a mask that looks like
Charleton Heston in the 10 Commandments. But then one must consider
their own perception of their preferred deity…

Thanks for allowing me a bit of humor on an otherwise dreary Friday.

Rick Copeland
Silversmith and Lapidary Artisan
rockymountainwonders.com