Using Raman microscopy and scanning electron microscopy we have successfully identified, for the first time, synthetic silicon carbide (carborundum) particles in 15 unearthed relics and assorted remains from five out of six Neolithic sites (~4000 - 7000 years b.p.) in Eastern China. Because of its extreme hardness, silicon carbide was apparently employed in the manufacture of ancient jade artifacts presumably as an abrasive for polishing. We show that Neolithic people may have already used this synthetic material to carve and polish both jade and quartz artifacts, contributing to the blooming development of the jade culture throughout ancient China.