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Polishing Emerald Slices


#1

What would you recommend for polishing Emerald slices and also
tourmaline slices? We have felt wheels, aluminum wheels and copper
wheels available also tripoli, aluminum oxide and chrome oxide
readily available.

Best regards,
Robert P. Lowe Jr.
Lowe Associates - Brasil
Gemstones, Rough, Specimens
e-mail: robertplowejr@juno.com
(in the USA 22 Aug. - 31 Oct.)
e-mail: @Robert
(in the Brasil after 31 Oct.)


#2

Robert, both materials polish nicely using .04 micron aluminum oxide.
You can use leather disks if you don’t need a real flat surface or a
lead or tin type lap if the surface needs to be optically flat.


#3

Robert,

I have had good success polishing Tourmaline slices using Tin Oxide
on a leather end plate. I don’t see why it shouldn’t work equally as
well using Tin Oxide on a hard felt wheel. Tin Oxide is my all purpose
polish for Tourmaline, Beryl and Agate. I think its a little more
expensive than some others, but sure gives a high polish. Haven’t
tried the chrome or aluminum oxide on tourmaline and Beryl.

Douglas Frey
@d.d.frey
www.dfrey.saskatoon.sk.ca


#4

I am interested in what others say on the subject. My personal
experience regarding tourmaline slices is that you cannot polished
them successfully with something like a Genie because of the curvature
of the wheel. They need to be polished flat like on an All-U-Need. I
have lots of crummy watermelon tourmaline slices that I thought I
could fix by repolishing them, and it doesn’t work if you are using
curved wheels - the center of the stone doesn’t get polished unless
you dome it, and then you lose your flat slice look.

Carol —


#5

Robert, you can use Sapphire type “A” powder (.3 micron) for the
tourmaline and emerald; I have gotten a slightly better polish on the
emerald with top quality (Super)cerium. Johnson Brothers
(818-705-7400) sells both. I polish slices on a flat lap like the All
U Need by Hi Tech–I use their Tech 10 polish pad which is comparable
to a hard felt. Bill Navran


#6

Howdy Robert, Realizing there will be a lot of suggestions and some
experiemntataion on you part will yield a good working solution for
you I will offer a couple of starting points to try. You should
definitely use the AlOx for the tourmaline. If not requiring perectly
flat surfaces try a water ‘slurry’ or paste of AlOx on the felt. Use
of a drop of liquid detergent may help. Use a spray or squirt bottle
occasionally to keep the felt dampish. large pieces could be handheld
but attaching to a dowel stick (dop) 4-5" long allows more (and
safer) control. remember, you’ve already prepolished it flat right? So
the polishing will not really remove that much material. Flatter
surfaces will certainly be obtained on the copper (flat disks?)
wheels. If the water slurry doesn’t work try an oil based carrier
(WD-40,Stoddard solvent,olive oil,etc.). Most of my faceting related
polishing occurs well under 500 rpm on 8" discs. Though my forst
choice for emerald would be cerium oxide, I’d try the above techniques
with Chrome and AlOx. The aluminum may not work well as is but a hard
paste wax (carnauba) applied first then used with an oxide slurry may
work well. have you thought of trying a CD-Rom? Do you have access to
caste acrylic sheet? Let us know what works for you OK? Carl 1 Lucky

Texan


#7

Hi Robert,

Do you have access to enough end-grain Cocobolo, Purpleheart,
Goncalvo Alves or Ironwood to make an 8-10" polishing lap, or can you
gain access to a decent (flat) copper lap? If so, after first
smoothing out your slices on the X-fine (1200 mesh, or better) SiCarb
grit we’d once discussed, I’d suggest you try using a thin, watery
slurry of Aluminum Oxide (2 Tbsp. of AlO2 and three small drops of
dish detergeant in a pint of water, well shaken, then applied to your
polishing lap with an eyedropper or paintbrush), and keeping the
lap’s surface damp, neither wet nor completely dry. The friction
between lap/compound/workpiece will take care of your polish in short
order, but only if you’ve taken the time needed to effectively
prepolish each piece. Are you heading up to MA, this trip? If so,
you’re welcome to stop by my place for some hands-on coaching. Just
drop me a line or give a ring, if you’re going to be on the area.

Best Regards,
Doug Turet
Another Bright Idea!
P.O. Box 162
Arlington, MA 02476
(781) 643-0389
@Douglas_Turet
www.anotherbrightidea.net


#8

Look at the Diamond Pacific Catalog. You can install flat wheels on
your Genie. You can also put removable flat laps on either end of your
machine. I have rigs set-up with different types of wheels. Finish
with 50,000 grit/micron on your flat lap. Don’t use the syringe method
on leather. Buy the diamond charged flat laps from Diamond Pacific.
Use a good pump! This is clean and easy and a good way to do
tourmaline or most any slices.

Galen A Rossop
New World Gems
The Gemstone Supermarket


#9

Robert, In my commercial lapidary the cabbers use flat laps for
sanding, pre-polish and final polish. 1 grit diamond powder works very
well for the final polishing and produces excellent results.

Yath M Iqbal
Intergem Exports and Ceylon Sapphires International