Daily Wire Tip Jan. 24: Tumbling Lapis and Other Natural Stones
Daily Wire Jewelry Making Tip for
January 24, 2011
Question:
I put a lapis lazuli pendant in a rotary tumbler to harden the wire, and when I took it out, the lapis had faded. How do you know what kind of stones to put in a tumbler?
-Wanda in Lexington, Kentucky
Answer:
Unfortunately Wanda, it sounds like you have either a dyed "other stone" cab or a dye enhanced/treated lapis cab, as true lapis will not "fade" in a tumbler or in any other situation short of lying in direct sunlight for many years.
Although a lot of people use a tumbler to give their wire jewelry pieces a final polish or to harden soft wire settings, I have been tumbling rocks for many, many years therefore I have never, ever, put a finished jewelry item into a tumbler! (Personal preference only.)
W-S Faculty member Mary W. Bailey interviewed several jewelry artists and wrote a great article about using a tumbler with jewelry, Tumbling Your Jewelry, and we have had some good discussions about using tumblers such as: Tumbling Finished Jewelry and Tumbling – It’s a Toss-up! that include readers’ comments about tumbling different materials.
Basically, using a tumbler on soft, porous or dyed stones is not recommended, but if you were sold an item that was misrepresented, you have no way of knowing whether or not it will tumble well except by experimenting.
Answer contributed by Dale “Cougar” Armstrong
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Filed under:Cleaning, Polishing, & Care‚ Daily Wire Jewelry Tips‚ Light Lapidary‚ Project Help
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same thing happened to me with lapis using an ultrasonic cleaner.
Soft stones definitely do not belong in a tumbler!! The hardness
on the stainless steel shot is about 5.5 on the Moh’s scale of hardness.
That basically is about the hardness of glass. Any stone harder than
that is candidate for the tumbler.
Quartz type stones are the only stones I would ever consider putting
in a tumbler.
Good answer. I, too, would never put a jewelry piece that contained any kind of stone in a tumbler. Just wire? That’s a different story.
Dear Wanda,
sorry about your experience with the “lapis.” Its painful to do the work of setting a stone and having a mishap. I have had pretty good luck tumbling finished pieces with walnut shell medium. The pieces need a good wash and some picking out of the shell between wires, but it does a good job overall. I have never had a stone damaged.
Happy wrapping!
Chris
A little tip to help-sometimes- to tell if a stone is dyed. If it is a stone which naturally would have some white in it-which all but VERY expensive lapis do- and there is no white in your stone, it is probably dyed.
About tumbling – I started out as a metalsmith only so I have been tumbling stuff a long time, using Super sunsheen burnishing compound and stainless steel shot. I have tumbled all kinds of stones and glass with no problems. If you have enough liquid and the proper proportion of media and liquid to stone the shot never actually hits the pieces being tumbled, because there is always a molecular layer of fluid between the piece and the shot.The shot pushes the fluid against the pieces with the force to polish, but not scratch.
Thanks for your explanation of how a tumbler works to polish jewelry Mildred!