I was looking at Wikipedia, and trying to figure out why rubies are called rubies, and not called red sapphires, even though they are the same gem stones, only with slightly different trace impurities. (Sapphires can be blue, pink, yellow, salmon/padparadscha, purple/lavender, green, orange, or brown.)
I did not find the reason for the different names, it appears to be an accident of history, but as Wikipedia searches often do, the led me down a tangent, where I was looking up emeralds, and found out that there is such a thing as a scarlet emerald:
In geology, beryl is a mineral composed of beryllium aluminium cyclosilicate with the chemical formula Be3Al2Si6O18. The hexagonal crystals of beryl may be very small or range to several meters in size. Terminated crystals are relatively rare. Pure beryl is colorless, but it is frequently tinted by impurities; possible colors are green, blue, yellow, red, and white.
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Emerald is green beryl, colored by trace amounts of chromium and sometimes vanadium. The word “emerald” comes (via Middle English: Emeraude, imported from Old French: Ésmeraude and Medieval Latin: Esmaraldus) from Latin smaragdus from Greek smaragdos – σμάραγδος (“green gem”), its original source being a Semitic word izmargad () or the Sanskrit word, marakata (मरकत), meaning “green”. Most emeralds are highly included, so their brittleness (resistance to breakage) is classified as generally poor.
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Red beryl (also known as “red emerald” or “scarlet emerald“) is a red variety of beryl. It was first described in 1904 for an occurrence, its type locality, at Maynard’s Claim (Pismire Knolls), Thomas Range, Juab County, Utah. The old synonym “bixbite” is deprecated from the CIBJO, because of the risk of confusion with the mineral bixbyite (also named after the mineralogist Maynard Bixby). The dark red color is attributed to Mn3+ ions.
(emphasis mine)
As some of you are no doubt aware, the phrase “”scarlet emerald” figures prominently in what is arguably the worst piece of fantasy ever written, The Eye of Argon:
Glaring directly down towards her was the stoney, cycloptic face of the bloated diety. Gaping from its single obling socket was scintillating, many fauceted scarlet emerald, a brilliant gem seeming to possess a life all of its own. A priceless gleaming stone, capable of domineering the wealth of conquering empires…the eye of Argon.
(emphasis mine)
Yeah, it ain’t what one would call “deathless prose,” but the fact that there is such a thing as a “Scarlet Emerald” is amusing.
I once competed in an Eye of Argon reading, you lose if you laugh or misread the text, (including its many typographical errors), and I laughed so hard I had to sit down, and the knife handle in my back nearly broke a rib. (I was wearing the official Klingon retired officer uniform)