In which decade did Madagascar become a significant source of blue sapphires?

Madagascar emerged as a significant source of blue sapphires in the 1990s, particularly beginning around 1998 when large quantities of the gemstones were discovered in the area's gem-rich regions. The discovery revolutionized the supply of sapphires in the global market, offering an alternative to traditional sources like Kashmir and Sri Lanka. The quality of the sapphires from Madagascar was appreciated for its vibrant color and clarity, making the gemstones highly desirable among gem enthusiasts and jewelers alike. This pivotal moment marked Madagascar's rise to prominence in the colored stone industry, solidifying its status as a key player in sapphire supply during the late 20th century.