Different Mills/Stones - Need your thoughts AND History knowledge!

Hello,

After much reading etc... I came down to a few conclusions.

1: I want a stone mill. - This is how things got done since the beginning of man.

Cool, so my options are limited to Retsel, Shnitzer, Komo? Waider and Salzburger.

Everything else seems to be running steel burs or the impact method (like wonder mills) which honestly... I have no desire for.

So what is my dilemma?

Well - I might be being very picky and fussy about something that is not really a problem to begin with...

The stone mills mentioned either use Carborundum, or, Corundum/Ceramic.

To my understanding, the more 'pure' method is the Corundum/Ceramic rather than having glue and other foreign matter holding the stone together.

However, Corundum has Aluminium Oxide (Al2O3).

Over time as a home grinding machine, rock powder (thus Al203 as well) will end up in the flower and eaten as bread.

Alzheimers as well as other health issues... that does not sound very positive to me.

Then I found Salzburger. I was very happy to be honest. Reading how they use 'pure' stone (granite), nothing man made... basically the way nature intended.

I want to do things the way they used to be done centuries ago, they would of used 'pure stone'. 

So I found my mill!

However - 

As I read up on Granite... it also has Aluminium Oxide (Al2O3).

So what is my question?

Well, wanting a stone mill, is there any way to have something 100% free from Aluminium Oxide?

What kind of stone did they use say 500 BC, 600 BC etc during the babylonian empire and prior to that?

Israel back in those days used to grind there own wheat into flour. Bread was part of the religious service (table of shew bread) in the tabernacle. 

What kind of "mills" or "stones" did they use in that milling process?

Was it Granite? Was it other stones I am unaware of that are free from Iron Oxide and Aluminium Oxide?

Does something like that exist, or not and am I really being fussy over nothing or what? 

It is easy just to say "Yeah dont worry about it, im still alive and I never felt any problems" - But I mean... like 'really', with no risks, not just "it worked for me". 

Try be informative, why yes or why no etc so I can 'learn'.

Btw- Does anyone have any experience with Salzburger Granite stone mill set on its finest setting? How fine is the flour?

Thanks
George