“Diamonds are Forever” A marketing campaign that moved the diamond buying audience from only the elite population to everyone, a James Bond movie was even named after this slogan. Diamonds are arguably the most popular gemstone, desired for their exemplary brilliance, durability, and versatility. Diamonds are commonly used as center stones for engagement rings, earrings, pendants, bracelets, and accent stones for colored stone pieces. Diamond is the birthstone for April and is a common 10th, 20th, 60th, and 75th year anniversary gift.