when corundum synthesis was perfected, a long-held marker of status and wealth was shockingly destabilised... OR WAS IT? Today I will bust open the Ruby Myth and show rubies and sapphires have never existed. Vote corundum, the earthly representative of a legend https://twitter.com/MineralCup/status/1310491875963318273

or in other words I'm going to talk about how what's meant by "ruby" and "sapphire" over the course of human history is surprisingly slippery stuff, and why that's interesting

The reason there are so many references to rubies and to a lesser extent sapphires in history and folklore is, to a large extent, that those terms used to be used much, much more loosely. For example, this is is the Black Prince's Ruby. actually, though, it's a spinel

Were the English mistaken in the identity of the stone? were they deceived? nope, there was then no distinction made between the ruby and the spinel. There's no particular reason why corundum should have kept the appellation "ruby" while spinel was disinherited.

Like, people knew spinel was slightly different to corundum, and gave it a different name (Balas ruby) but in the same way you might be aware that particularly deeply coloured rubies from Burma are called "pigeon's blood rubies". you don't think of them as a distinct mineral

A lot of famous rubies of history are spinel. The Timur Ruby, a gem with an incredible history, is a spinel. But historically, culturally, in its time spinel WAS ruby. It didn't so much get discovered as get the sack
https://www.rct.uk/collection/themes/exhibitions/victoria-albert-art-love/the-queens-gallery-buckingham-palace/the-timur-ruby-necklace

Nadir Shah of Iran engraved the Timur Ruby thus: "This (is) the ruby from among the 25,000 genuine jewels of the King of Kings... which in the year 1153 [1740 AD] from the jewels of Hindustan reached this place."
image: https://torontoguardian.com/2018/08/emperors-jewels-exhibition-aga-khan-museum/
text: https://www.gemselect.com/other-info/timur-ruby.php

like, are you going to correct him or

It wasn't just corundum and spinel; pretty much any red stone could be described as a "ruby". What does "ruby" mean, anyway? just "red".
https://www.etymonline.com/word/ruby 

"carbuncle" was used in a similar way to "ruby" to mean any red stone. Honestly I don't think we stopped saying "carbuncle" because we were so into precision, we dropped it because it was too gross; it had started meaning "boil, lesion, zit"

What about "sapphire"? Unlike "ruby", this wasn't a broad label for any clear blue stone that became more specific with time; it's referred to a number of different clearly distinct gems, possible due to misinterpretation of ancient texts.

Theophrastus talks about a dark blue stone called "sappheiros", but he says it's easy to carve into seals, opaque, and sometimes flecked with gold. we have lots of examples of lapis lazuli sealstones; here's one contemporary with Theophrastus (300BC ish).
https://www.britishmuseum.org/collection/object/G_1867-0507-545

i do not wish to leap to conclusions about the identity of the mysterious "sappheiros", however,

Theophrastus describes "sappheiros" as being similar to a stone called "kyanos", but darker in colour; it's pretty likely they're different grades of lapis lazuli.

theophrastus is rad btw. he feels really contemporary. dude is just describing things and trying to figure out how they work and vibing. a true scientist. you can access the translation of his "on stones" i've been using here: https://kb.osu.edu/dspace/bitstream/handle/1811/32541/THEOPHRASTUS_CALEY.pdf?sequence=1

Pliny is the smug New Atheist guy who's always going on about Western Civilisation and hoarding hydroxychloroquine. Theophrastus is the botany postdoc who's quietly sectioned off a corner of the greenhouse for psychedelic plants. read Theophrastus https://www.theatlantic.com/science/archive/2016/06/the-man-who-invented-botany/485780/

"invented botany" is a bit much but the article otherwise described Theophrastus' charm very well