It is very interesting that we can make synthetic rubies and sapphires for industry from powders of alumina oxide and chromium oxide, sapphires only need the alumina oxide powder.

I am not an expert, but, I have researched this and tried my own home ruby heating experiments. One thing I learned is, when they heat treat Rubys, they heat them to the temperature at which they  melt but do not liquify, and that temp allows some impurities and inclusions to escape, but it also allows cracks to melt back together. This temperature is held and maintained for day to weeks even months at times. Then they allow them to cool and this process is done extremely slow, sometimes taking weeks to cool down. This is done to prevent cracking or old cracks from reappearing. I tried heating a ruby before I did any research and all I did was destroy the color and turn it into a brittle crumbly piece of junk. I heated it quick with a propane torch and let it cool in the air.

I'd have to think the 2300-2400 F destroying the impurities is the reason that one crumbles. It was full of impurities. The normal treatment for ruby is 1800 C; 3200-3300 F.  That's "way above" what you did. And it doesn't make "normal" rubies crumble. (if you went to 2400 C, you went way to hot, and that would possibly be why it fell apart as well...)

I like that they fluoresed better but they seemed to become lighter in color not more transparent

Great video. Great experiment. I love Ruby’s.

When sapphires and rubies are heat-treated , it's usually In an oxygen free environment. They are heated to just below melting temperatures and held there for many hours. Sometimes the person heating them will do an initial heating and then a secondary where certain things are added in a gas form to enhance colors. It's pretty wild. The heating that's done over coal or wood fires with bellows and foil in small villages is actually to remove the secondary blue under tones . I think these COULD be treated but it would need something extra to help. Like sealing the furnace and purging it with argon gas or nitrogen gas and perhaps adding a dusting of sub nanometer fine chromium and aluminum oxide powders to melt in . An aluminum oxide ceramic crucible may do the same thing as the powder.  Something or nothing at all lol. A microwave kiln and a long heating could get it hot enough. That may just melt them though.

Has been a while, nice to see you are still around.

I'm pretty sure a lot of corundum is dyed, so not only the red color disappears, but more of the fluorescent areas are exposed since the dye cooked off.

Glad you're back, and with an interesting prospect too.

Beautiful sharing 😊

Vết nứt không tự liền bằng cách nung nóng mà họ sẽ đốt với silica để phủ ( khác với thuỷ tinh chì ) . Bạn không nên để hở vì oxy sẽ làm đá nứt

Beatyful

I try my sapphire stones this can work's 👍 get good shine and craks fill need 100 of time short time heat and sudden cool , that is work's

❤

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❤Thunkyou

I think what went wrong here is that you overcooked them. I've seen it mentioned in papers before, but if you overheat a gem while treating it you can destroy it, causing it to lessen or even lose it's color and become unstable, just like the rubies here did.

perhaps you might have more success treating higher quality corundum's? buying some sapphire gravel from gem mountain might provide a good amount of stones to test on. they usually have a lot bigger of a reaction to treatment :D

I'm gonna try this with a different method that I''ll reveal when I post the vid of the results

The oven is apparently powerful.  How much electricity did it consume?

I’m sure there are other better way to heat treated, I’m myself has been looking in a different way to heat treated .