One of the interesting ways I found out about this was in a history class that was talking about "royal" fabrics. These were fabrics that only royalty could own. And while there was the general "lets make a rule to distinguish us from the common people" there was also that challenge that some colors were so rare because the pigments were only available to make them in very small quantities. As a young man it amazed me that people had fights over what color clothes you could wear or that purple pants would be 10x the expense of white or grey pants.