Diamonds—which are April’s birthstone—have reigned supreme as the planet’s most desirable gemstone since before they first surfaced in Italy’s marketplaces in the 15th century, reportedly excavated from India’s Golconda riverbeds. (Some historians estimate that India was trading in diamonds as early as the 4th century BC, and were coveted by the country’s very wealthy classes). As demand grew, additional diamond deposits surfaced in South Africa, Brazil, Canada, and Australia. Today, Botswana is the world’s most fruitful supplier (followed by Russia), delivering more than 140 million carats of diamonds each year. Tired, dusty-looking diamond designs are a dime a dozen, but these five jewelers are keeping the gem current with completely fresh creations.