You might consider using cerium oxide and make a slurry with optical
grade cerium oxide powder mixed with distilled water and apply it to
leather, or you may choose to use the 3M Trizact polishing belts and
discs.
For polishing the facets on quartz, obsidian, feldspar, and opal, I
make a slurry with distilled water and Rhodite 904 cerium oxide
purchased from Universal Photonics, Inc. in New York. I paint the
slurry with an old make-up brush on a special polishing lap just for
cerium oxide. Steve likes the cerium oxide belts and discs for
polishing his carved opals and other silicate gem materials, and
these products are carried by Santa Fe Jewelers Supply. The belts are
affixed to wheels on a stationary carving machine, and the discs are
attached to hand-held carving tools.
http://www.ganoksin.com/gnkurl/ep8001
http://www.ganoksin.com/gnkurl/ep8002
From 3M
http://www.ganoksin.com/gnkurl/ep8003
3M Trizact Lapping Film 569XA
Microreplicated abrasive product using tightly graded cerium
oxide mineral coated onto a PSA (Pressure Sensitive Adhesive)
polyester film backing.
Over the years, we have found that the use of cerium oxide imparts
an excellent polish on quartz, glass, opals, and other gem materials.
Nancy and Steve Attaway