A regular stone vs a shiny diamond.

A regular stone and a shiny diamond are lying side by side.
Which one do you think people will prefer, adore and take home?

:) Exactly.

Now, the diamond has been picked up by someone, leaving the 'invisible' regular stone behind.
A ruby came. It is now lying beside the regular stone.
Which one do you think people will prefer, adore and take home?

:) Exactly.

Then, someone picked up the pretty ruby and take it home.
A moment later, a sapphire came.
...

Well, you now the pattern.