[Rockhounds] Cleaning Galena, Help?

[jbacko]

Paintricks at aol.com wrote:
> 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
>
>   
The dull coating on galena is often cerussite, PbCO3. It is not really a 
coating but rather a gradual penetration of the surface to some depth as 
the sulfide is transformed to carbonate. It is almost impossible to 
remove altogether  without cleaving the affected area off the crystal.  
Most galena that is exposed to weathering for any length of time develop 
this coating.


john