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Suggestions polishing Chilean Lapis


#1

Hi There,

I am hoping someone can help me and offer some suggestions /
recommendations to polishing Chilean Lapis. My talent is a little
different than your typical jewelry as I am a pen maker. I have made
the bodies of my pens from turning Turquoise, Malachite, Marble and
now Lapis on a mini lathe. The problem I am having with the Lapis,
and hope you can offer some suggestions, is in the finishing of the
Lapis. I am looking to achieve a very high gloss polish finish on
the stone similar to that in which you find in jewelry, but so far
have been unsuccessful. The stone is beautiful, but I can’t seem to
bring the luster up to a high shine.

Please let me know what type of compound I should try in order to
achieve this and any techniques you might suggest as well.

Thanks for your time and sharing your

Sincerely,
Patti O’Connor
Exquisite Turnings


#2
I am hoping someone can help me and offer some suggestions /
recommendations to polishing Chilean Lapis 

Getting a high gloss polish on any Lapis regardless where it’s from
can be a challenge. Lapis is naturally a porous stone Traditionally
Lapis is waxed to produce a higher gloss finish. If you want to
remain a purest then the finer sanding you can do the better.

I generaly sand Lapis to 600 and polish with ZAM which is Chromium
oxide with a wax binder so in a sense I’m using wax on the stone. I
have also placed lapis cabs under and incandescent light bulb to warm
it then applied liberal amounts of Renaissance wax, let it cool, then
buff with ZAM. About the same results as when using jut ZAM.

You might try some of the turning waxes and polishes available from
turning suppliers like Woodcraft (woodcraft.com).

Rick Copeland
Silversmith and Lapidary Artisan
rockymountainwonders.com


#3

Problem with most Chilean lapis is the large amount of calcite
present which tend to undercut badly when polishing. You need to
fine sand via 1000 grit and then 2400 grit and polish on a very short
nap cloth such as silk or on leather. Almost any polish will do, tin
oxide, colloidal silica, diamond, alumina etc but 0.5 micron or
less. 0.05 for silica or alumina are my preferred polish sizes after
prepolishing with 6 and then 3 micron diamond. By using a lot of
stages for a short time you dont get polishing relief for the
different hardnesses of the minerals present.

Nick Royall