Removing calcium deposits

Jewelry Discussion
1

hi there! can you please tell me how to take the calcium deposits off
of the shells i am working with? i’ve tried a grinder but the
surfaces are uneven. what can you suggest? thankyou carla jensen

2

Carla, All you need to do remove the calcium is place the shells in a
pyrex dish of warm apple cider vinegar cut with a bit of water. Let
them soak for about 30 minutes and rinse. Calcium that didn’t
disappear can be knocked off. I would suggest using Muriatic acid
but that can be pretty strong and hard to gauge the length of time of
soaking.

Cheers from Don at The Charles Belle Studio in SOFL where we are
getting ready for the big Palm Beach Gem and Mineral Show, and where
simple elegance IS fine jewelry! @coralnut2

3 
       All you need to do remove the calcium is place the shells in
a pyrex dish of warm apple cider vinegar cut with a bit of water. 
Let them soak for about 30 minutes and rinse.  Calcium that didn't
disappear can be knocked off.  I would suggest using Muriatic acid
but that can be pretty strong and hard to gauge the length of time
of soaking.

Don, I’d think one would have to be very careful with choosing which
acids. the shells, after all, are also calcium carbonate, and just
as subject to attack by acids as are the calcium deposits themselves,
with the exception perhaps of the porosity of those unwanted
deposits, which might allow them to be attacked quicker. One would
have to be very careful not to leave shells in anything that could
attack the deposits, any longer than needed, to avoid having too
much of the shell itself be dissolve also, I would think. Have you
found shell to be that much more resistant to such acids as to make
this worry unfounded?

Peter

4

Peter, You are correct…that is why I recommend vinegar cut with
water. It is quite mild and more easily controlled. The harder
nacre surface of the shell itself tend to resist the vinegar long
enough that the unprotected and (as you say) more pourous calcium can
be either burned away or softened. I would not go so far as to say
this should be an unfounded worry, but if one keeps a good eye on the
process, the shell can be rinsed quick enough to preclude damage to
the shell itself.

A hot water/vinegar mixture is also used to whiten hard coral beads.
Then they can be dyed if one wishes or left white. I have made
quite a few of them. I also use this mixture to clean calcite
crystals that we find on/in shells in SOFL quarrys

Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry! @coralnut2