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Re: calcium tablets
A reader previously wrote:
> >What about blackboard chalk pieces ?
Blackboard chalk was traditionally pure CaCO3. Two or three years ago I
suggested chalk as a source for calcium and Paul Sears pointed out that
chalk these days isn't always CaCO3. I checked what I had; it wasn't.
Check yours before you try using it. If it is CaCO3 then it should fizz
when hit with a drop of vinegar.
If you find some blackboard chalk that is CaCO3 then it should be a
useful source of calcium.