[ANON POST] Persuading Lavoisier that Sapphire Is an Element

[orange_fell]

I'm writing a story part of which is set in 18th Century Paris shortly after Lavoisier's publication of Méthode de nomenclature chimique. One of my characters wants to convince Lavoisier that Sapphire is an element. They do not need to succeed but I'd like an idea of the evidence they might put forward and how (and if) Lavoisier might counter it.

Comments

[anonymous]

Ooh! I think I may have answered this myself. For the record Lavoisier lists alumina among his elements which is aluminium oxide which, at the time, no one had been able to decompose. Since sapphire is an aluminium oxide I'm guessing he would have included it among alumina in which case he would have concurred that Sapphire was an element.

[orange_fell]

Would he have known to make a connection between "alumina" and sapphires? Did his book make any mention of other gemstones, such as diamond as a form of carbon?

[anonymous]

*googles frantically*

It seems it was Lavoisier who discovered that diamond was a form of carbon, so he did know that though it was obviously a recent discovery. Apparently alumina is something previously called Argilla (Lavoisier recommended a name change as part of his nomenclature). I've found a book on Google docs from 1811 which says Sapphire was identified with Corundum which is identified as Argilla durissima by 1802 (so about 15 years after Lavoisier's book). That's a little after my story is set, to be honest, but close enough for rock and roll and Lavoisier must have suspected something similar or presumably he would have included them separately in his table.

[orange_fell]

Very cool! It seems pretty logical, then, for both Lavoisier and your lady character. If gold, silver, and diamonds are all chemical elements, then it would probably follow to an 18th-century mind that sapphires and other precious materials are too.