Yes, of course you're right, from the song, sapphire is the King's stone. I have one rectangular that I bought myself after a dream and wear when I need strength and protection, but alas am without a white bellied beloved to lay it upon. It is a good reminder to get it out and around my neck again.
I've hunted for beryl in the Utah desert, but never lucky enough to have found a real one.
Sapphire was used by the Etruscans over 2,500 years ago and was also prized in ancient Rome, Greece and Egypt. Revered as a stone of royalty, sapphire was believed to keep kings safe from harm or envy. It was also purported to protect you from dishonesty, fraud, terror, poverty, and even stupidity and ill temper.
The three crossed lines in a Star Sapphire have been said to represent hope, faith and destiny, and in German lore it was considered a stone of victory. (healingwithcrystals.net)
sacre bleu is sacred blue, says Christopher Moore who wrote a book with the same name.
henri de toulouse-lautrec