The value of diamonds as an investment is of significant interest to the general public, because they are expensive gemstones, often purchased in engagement rings, due in part to a successful 20th-century marketing campaign by De Beers.[1][2][3] The difficulty of properly assessing the value of an individual gem-quality diamond complicates the situation. The end of the De Beers monopoly and new diamond discoveries in the second half of the 20th century have reduced the resale value of diamonds.[4] Recessions have engendered greater interest in investments that exhibit safe-haven or hedging properties that are uncorrelated to investments in the equities markets.