NICOLE SINCLAIR: We’re told that diamonds are forever. Not just James Bond, but brides all over the world know this phrase. The diamond ring is synonymous with getting engaged, but this tradition, like the diamond business itself, is the product of clever marketing from a company that had just about a monopoly on the business for a century. That and other tales of how one gemstone came to dominate the jewelry industry can be found in the new book, “Brilliance and Fire, a Biography of Diamonds.” The book’s author, Rochelle Bergstein, joins us now. Welcome, Rochelle. RACHELLE BERGSTEIN: Thank you. NICOLE SINCLAIR: I want to start with the idea of the diamond with getting married. We usually think of the diamond rings as being exchanged during the engagement period, but this wasn’t always the case. How did that come about? RACHELLE BERGSTEIN: Well, before diamonds were discovered in South Africa in the late 1880s, diamonds were legitimately rare. They were only owned by royalty and by people in this country who had made a lot of money doing things like building the railroads. After diamonds were discovered in South Africa, they became available to a much larger swath of the population. So because of that, jewelers started thinking about ways they could sell diamonds to average people. And one of the ideas that came about was the diamond engagement ring. This was in the early 1900s, so at the turn of the century, and the diamond was the stone that was used most often in engagement rings, but it wasn’t the only one. People gave diamond engagement rings with pearls, with sapphires, all sorts of gemstones. In 1938, when the Depression had really cut into the American economy, the company De Beers, hired an advertising firm to help reinvigorate the social custom of giving an engagement ring. It had really gone out of style, and younger people in particular, who were the ones getting engaged, of course, were really not that interested in doing it. So they hired an advertiser, who created a set of print ads that made the diamond engagement ring feel really timeless. They wanted the product to feel classic and almost as if something that the knights were giving their ladies back in the Medieval times. And they accomplished it. And now, of course, when people give a diamond engagement ring, we feel like it’s something that people have done forever. NICOLE SINCLAIR: Right, always. Another story that you go into in the book is the tale of the Hope Diamond. RACHELLE BERGSTEIN: Mm-hmm. NICOLE SINCLAIR: Can you tell us a little bit about that and how it speaks to the rise of the diamond industry and also Cartier, in particular. RACHELLE BERGSTEIN: The Hope Diamond is probably the most famous gemstone in America. It is a blue diamond, which not a lot of people know. It’s currently housed at the Smithsonian. And it has a fascinating history, because many people believe it is cursed. Whether or not that is true, Pierre Cartier, who got his hands on it, again, at the turn of the century, he used that story to his advantage to sell it to a young, capricious socialite with a lot of money on her hands called Evalyn Walsh McLean. He met her on her honeymoon, and she bought a very, very expensive gemstone from him in Paris. He then moved operations to America. His brothers kept the French store, and he moved to New York. And when he got the Hope Diamond, he recalled the way that she had been interested in getting a very spectacular gem. So we went to her hotel room, and he told her this really amazing outlandish story about how Jean-Baptiste Tavernier, who was a diamond dealer, found it in India and plucked it from the Third Eye of a Hindu god who then cursed Tavernier and cursed the stone. And he used it as a sales pitch. He leaked stories about the Hope to the press. And the American public loved hearing about a stone that was so evil that it cursed the wealthy people who bought it. You know, there’s something fantastic about the idea of a product that is attracting wealthy people and then ruining their lives. NICOLE SINCLAIR: Yes. I could see that. You also talk about consumers hold brands like Tiffany’s, Bulgari, Harry Winston in high esteem. And you talk a little bit about how these namesakes were, in essence, show men. How did that play into the public’s perception of the diamond? RACHELLE BERGSTEIN: You know, Charles Lewis Tiffany, Harry Winston, these men really understood the power of the press. Tiffany, when he was starting Tiffany and Co, was one of the first American jewelers to compete on a global stage. You know, the heritage jewelers were all in England. They were in France. They had access to royalty and so they had access to really wonderful, grand stones. Charles Tiffany was a bit of an upstart. So he was able to make sure that the press knew when he was buying big diamonds. And at the time of Tiffany and Co’s popularity, he was considered the king of diamonds. Harry Winston did the same thing. He would get his hands on a very big diamond, and he would make sure the press knew about it. And then when a diamond was being cut, for instance, he would invite the press to come to his offices and watch. So they both really understood the media, and I think were maybe ahead of their time in that way. NICOLE SINCLAIR: And perhaps even more than, let’s say royalty, Hollywood’s actually played a really big role in promoting the diamond industry. What was their role in how the diamond industry evolved? RACHELLE BERGSTEIN: Well, Americans don’t have royalty, right? NICOLE SINCLAIR: Right. RACHELLE BERGSTEIN: What we have is celebrities. NICOLE SINCLAIR: Yeah. RACHELLE BERGSTEIN: And so the diamond industry understood that very early on. They were prescient in a lot of ways. Again, I can’t stress that enough. So the advertising firm that De Beers hired, they looked to Hollywood. And, in fact, started a little offshoot business in Los Angeles that went to the studios to convince them to make sure that actresses were wearing diamonds in their publicity shots. To get actresses wearing diamonds on red carpets in the early days of the Academy Awards. To make sure that there were sequences in films where diamonds were being featured, where a man would give his sweetheart a diamond piece of jewelry, and she would get incredibly excited. There is actually one really awesome story where the agent in Hollywood somehow convinced studio executives to change the name of the film from “Diamonds are Dangerous” to “Adventures in Diamonds” just to keep the message about diamonds really positive. NICOLE SINCLAIR: Wow, a lot of influence there. You’ve mentioned De Beers a couple of times. They’ve really controlled the industry for some time. Today, who threatens their dominance? RACHELLE BERGSTEIN: Well, the industry has changed in a lot of ways. At their peak, De Beers controlled 90% of the world’s diamonds, which is an enormous number. That didn’t mean they were mining 90% of the world’s diamonds, but they were marketing 90% of the world’s diamonds. Today, the industry is a little bit more diverse. There’s Rio Tinto in Australia. There is Alrosa in Russia. And so De Beers now probably controls about 30% of the world’s diamonds, which is a big drop. After the Conflict Diamond Crisis, they changed the direction of their business so that they were no longer marketing stones that they hadn’t mined themselves. NICOLE SINCLAIR: And I always think of Rio Tinto as that mining company, so I like thinking of them as a diamond company. RACHELLE BERGSTEIN: Yes. NICOLE SINCLAIR: Thank you so much, Rachelle. Very interesting stuff. RACHELLE BERGSTEIN: Thank you. NICOLE SINCLAIR: That’s Rachelle Bergstein, author of “Brilliance and Fire, a Biography of Diamonds.” What are your thoughts on the future of the diamond business? Let us know in the space below or on the Yahoo Finance Facebook page.