Exactly when humans discovered that diamonds were the only material that could be used to polish other diamonds is in dispute. However, we do know that early attempts to polish diamonds were crude, and often relied on simple tools. Hand driven bow drills and leather straps dipped in diamond powder were the only tools available, and the time-consuming effort of polishing a diamond was often a task given to slaves and servants. Not surprisingly, the earliest examples of diamond jewelry mostly featured rough diamonds, perhaps with just a small amount of polishing to smooth out surface imperfections. This all changed with the invention of the scaif, credited to the legendary Lodewyk van Bercken. His invention gave cutters a practical tool to begin faceting diamonds, unlocking their hidden beauty. Today's modern polishing still uses the same concept van Bercken developed more than 500 years ago.