Not shown: A ruby.

That’s a diamond in the National Gem Collection.

We looked at birthstones last week, but there are even pricier minerals and gems than the diamonds and emeralds we can find in stores.

Why so expensive?

Because Nature hasn’t provided us with very many of these beauties, as this video from Weird Science shows:

Featured image: Red diamond, in the National Gem Collection, by Cliff, who notes that it may be the only red diamond on public display.