Covelite cab polishing

I have a Covelite cabochon which was once a beautiful blue but
recently I looked at it and noticed that parts of it have some
discoloration, almost looks like a film. How might I polish this to
get rid of this “stain”? I have searched the archives and the
internet and can’t find anything.

Beverly Jones

Zam and then Fabulustre on medium muslim buffs work well. Separate
buffs for the Zam and Fabulustre though!


if it’s the mineral i’m thinking of that is a deep prussian blue
metallic colour with white matrix sometimes included, a slurry of
cerium oxide rubbed on with a very light touch should remove the
oxides that have built up. I was told by an old school rockhound
that it is from Peru and the mine is now covered witha highway and
there isn’t more to be had…so i buy up all i can when i see it (
usually at estate sales). There is nothing like the spectacular
metallic navy/prussian color and the cabs i’ve run across have always
been freeform - as though the same person cut them.Before Hurricane
Katrina i had almost an entire tray of cabs that were stored in a
fairly high humidity area, and only the ones without matrix developed
an oxide like film…i tried compounds, but found that the slurry
worked best, second only to sulfur free rouge intended for gold and thing that i did realize in experimenting was that it
cannot be submerged in any type of ammonia containing jewelry
cleaner. hope this helps…and if you know of a source ( and we are
talking about the same stone) please let me know about the
availability and a ballpark price range they charged you for the


Using a fairly thick slurry of Linde A or chrome oxide on leather
should do the trick. I would suggest looking up a local rock shop if
there is one in your area to obtain a small quantity of one of these

Jerry in Kodiak


I have had good luck polishing Covellite with Alumina (Linde A) on a
dampened piece of cushioned felt. Make sure you use real felt, the
wool kind, not the nylon “felt” commonly sold at the fabric stores. A
very slight amount of alumina will do the trick. You might also try
one of the “Miracle Fiber” absorbent cloths, either dry or dampened
with a little alumina. The discoloration is just an oxidation product
and is normal over time, especially if you live in or near a large
city with acids in the air, as Covellite is just CuS. If you don’t
have or can’t get the materials to do this, I’ll polish it for you
for free if you pay the postage.

Good luck,


My experience has been that I can get a great polish on covellite
with tripoli and red rouge. It is a copper metallic with a hardness
of 1.5-2. I have used liver of sulfur to get a beautiful purple sheen
on some cabs, does not work on all pieces I tried.

Richard Hart

I bought covelite from a friend of mine many years ago who told me
it was from Montana. He always cut it in long rectangles and long
keystone shapes. It has a metalic gun metal blue with pyrite shot
through it. My friend has since died so I can’t ask him more about
it. I always loved it as a men’s material, very masculine color. I
don’t know about polishing it, I did cut some once and it got the
water and my hands black.

Sam Patania, Tucson
My work can be seen at

The covellite I know about came from the copper mines in Butte,
Montana. It does have a beautiful deep indigo-blue color and we have
some rough, it usually sells for a high price although at this time I
do not know what the market price is. The mine in Butte may not be
covered with a highway but it probably has water in it. I have made a
few cabs out of the covelite, it is a copper sulfide ore, it is toxic
if you are polishing any amounts of it. I polished it like I polished
my copper jewelry pieces and it came out real nice.

Linda Johnson
lrj jewlery
born in Montana, found employment in Idaho