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WWII Pink corrundum


Does any one know if around the time of World War 11, maybe before
then what they did in Russia or Germany with corrundum? I have some
pink and white corrundum that is produced from the time of World War
11. May be before then but not much. With a diamond tester it tests
as diamond. Some one says that they may have added carbon to the
corrundum. Trying to find out the refractive index on it as well as
the hardness and critical angle so I can facet it. It was given to
me to facet a piece for them. The rest is for me to keep and do what
I want with it.

Thanks! Anne


Hi Anne,

Synthetic corundum has been produced since the turn of the century.
During the war it (and beyond) it was used as “jewels” (bearings) in
fine watches and other delicate machinery that required the wear
qualities of corundum.

ou can’t really “add carbon” to it; the reason the tester is testing
diamond is because it’s either a lousy tester or being used
incorrectly. it’s a common occurrence with some brands.

Happy cutting!
Wayne Emery


If you can get a specific gravity to confirm it is corundum. The
flame fusion method of making it has been around for well over a
hundred years. The melting of aluminum oxide and adding coloring
elements to get the desired color can add to RI and thermal
conductive testing, IE diamond tester. It should still be close to
1.77 with an SG of 4.00. Critical angle on colored stones depending
on the tone and saturation might or might not be as important unless
competition cutting but Google it or stay with 36 to 40. If dark
material drop some to lighten up. As far as the location of the
rough it could have come from any where and just found a home in that
area. My 2 cent maybe 3. The carbon question is moot in that if it is
crystallized I am not sure you can get a mixture of carbon in
aluminum oxide, I will check though, peaked my interest.