Actually, rubies are among the most valuable precious stones. They're certainly more expensive than diamonds of the same weight, and they rarely show up as large stones. You won't see the same huge chunks of rubies as you do of sapphires and emeralds. In that respect, they're actually somewhat more discreet rather than tacky. Any time you see a great big red stone, the chances are that it's a spinel or a garnet or something, not a ruby.
Rubies do show up in humongous sizes, but, as you say, not in gorgeous clear unincluded stones. I have a pendant of one gigantic round polished genuine ruby cabochon that weighs in at almost 800 carats (yes, that's right, eight hundred!), but it's totally opaque. A very pretty medium-dark raspberry color, it has a bit of a cat's-eye sheen (chatoyancy) to it, but it's not transparent in the slightest. It may not be clear, but it's a real ruby!
And therefore
not expensive: I paid about a hundred dollars for it, from my Bangkok gem dealer, who was selling it as a rather posh
paperweight! He was very amused that anyone would have it set to wear around her neck, and suggested it's probably making my neck muscles really,
really strong.
Plus I could use it as a weapon, if necessary...
And you're right too,
Elspeth, that the famous big royal red stones are spinels, also known as balas rubies: the Timur "ruby", the Black Prince's "ruby", both are natural spinels. But just as beautiful, I think.
Oddly, my gem dealer says that blue sapphires of this included, opaque type almost never show up in big monster sizes. (Because of
course I wanted one...) He didn't know why, but the biggest opaque cabochon blue sapphires he'd ever sold were around 15 carats apiece. You see really big
transparent blue sapphires, like Diana's wedding gift from the Queen Mum, but for some reason not that many opaque sapphires the size of my ruby. Weird...since sapphires, like rubies, are corundum.