I have collect some beautiful nephrite jade and chrysoprase rough
material and
learning to cab it.
Would you tell me -
How to polish nephrite and chrysoprase?
What polishing material to be use will better? What is the criteria?
Please advise, since I can’t polished it well. Especially nephrite
jade, I got bad result in polishing.
Mitchell in AZ
Mitchell,
First, understand that some nephrite just doesn’t like polish! A
lot depends on how it was slabbed, i.e., where the grain
is…remember nephrite is fiberuous.
I used to spend a loooot of time in the cutting houses in Taiwan
where they were cutting native Taiwan nephrite and later Siberian.
They used chrome oxide on an 8" felt or leather wheel turning at
least 1725RPM. Nephrite, like jadite, likes heat when being polished
so you want to get it pretty hot. If it is dopped, be careful or it
will fly off the stick. If you don’t have or don’t like chrome oxide,
linde A on a rubber backed loft leather plate will also do a very
good job.
For chrysoprase, it is a silica based material (quartz chalcedony)
and the standard is rubber backed soft felt with good grade of cerium
oxide. Run at slow speed (3-400 RPM) and keep the felt just barely
damp. If the felt tries to pull it away from you…it is polishing!
Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry! @coralnut2
How to polish nephrite and chrysoprase?
I use a slurry of tin oxide and water on leather for chrysoprase,
and make sure it stays wet while polishing.
For nephrite and jadeite both, I use a product called Holy Cow on
leather. It is a very fine abrasive, and on these two materials, I
use it dry. I push it hard against the leather, and feel it drag and
pull. Wear gloves or finger cots because it generates a good deal of
heat.
Jadeite tends to “orange peel.” To avoid this, use soft pressure
during the sanding and prepolishing stages. Be thorough and patient.
Use the Holy Cow on leather, and use it dry with no water. Have fun,
James in SoFl