Until 20th century it was very difficult to receive purple color in life.
Purple is the most famous and the most expensive ancient pigment.
To obtain just one gram of it more than 10,000 (!!!) sea snails were caught.
One gram of such pigment was equal to one gram of gold, so only kings could afford such a luxury thing.
In ancient Rome only some people could wear white toga with a purple stripe. In Europe at the end of the 16th century Queen Elizabeth passed a law that prohibited the wearing of purple by anyone except royal relatives.
Here you can see a ring with a deep purple amethyst, diamonds and small amethysts in white gold. Such a cocktail ring will be strongly associated with something expensive, luxurious and make a very strong impression