"Explained" is a documentary-series by Vox on Netflix. Each episode they give an overview of a different interesting topic. Past episodes include topics such as the water crisis, both the racial and gender wealth gap, monogamy, tattoos, the female orgasm, the stock market, eSports, Kpop, designer DNA and more. Through graphics, narration, photos and video, they break down each topic by giving a general overview and then delve deeper into the specifics.
In this episode, "Diamonds", they explain the factors that caused the fairly recent rise in popularity of diamonds. They detail the marketing, economical, psychological and physical forces that literally and metaphorically created the diamond industry as we know it.
Dig Deeper: Diamonds are considered, "Veblen goods", which are "types of luxury goods for which the quantity demanded increases as the price increases, an apparent contradiction of the law of demand."
Here's a Forbes article going deeper into that concept: