[Rockhounds] Cleaning Galena, Help?

[Rick Trapp]

Before using oxalic acid you would want to make sure there is no
calcite on the specimen. Oxalic acid would turn any calcite into
calcium oxalate, a virtually insoluble material.



VevaBailey at aol.com wrote:

   
Hi List!!
Try Oxalic Acid mix as directed on the package and heated. I use an old crock 
pot on low. It takes several days, but it works. I usually take an old 
brush/toothbrush and do a cleaning as I take the rocks out of the acid. 
Be sure to wear Goggles/glasses, gloves and an apron. 
Rinse in clean water, allow to dry.
Veva
 
 
_____________________________________________________________________
In a message dated 6/18/2008 11:04:37 AM Pacific Daylight Time, 
larryrush at worldnet.att.net writes:

Kevin: Weathered Galena is difficult to restore. I found half a dozen large 
cubes buried in leaf mold at a collector friend's house this Spring and 
tried my luck....(He had bought a truck-load at one time, dumped it there, 
and these worked their way down below the soil line) First, I tried Bon Ami 
and an old toothbrush for the worst one. You have to be gentle, since the 
ingredients in the scouring powder are harder than Galena. Results: cleaner, 
but not lustrous. Then I used the less strong acids; Phosphoric acid next, 
in medium strength and hot solution. Some good results. Next, I tried 
Sulfamic acid, same way. Better. Finally, I ended up using silver polish to 
try and restore the luster. Even better, not like the original, but a big 
improvement. If you intend to keep your piece in a collection, I would skip 
the Bon Ami.

Good luck.....Larry Rush

----- Original Message ----- 
From: <Paintricks at aol.com>
To: <rockhounds at lists.drizzle.com>
Sent: Tuesday, June 17, 2008 11:18 PM
Subject: [Rockhounds] Cleaning Galena, Help?


  
  
    Hey everybody.  I have some nice Galena crystals that have an  oxidized
coating i need off.  It's a dull grey like your tire weights have  after a 
few
thousand miles.  This stuff is beautiful underneath.  Any  suggestions?
 Thanks in advance,
 Kevin



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-- 
Rick Trapp
Geologist/IT Manager, Arizona Geological Survey
rick.trapp at azgs.az.gov





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