Sơn mài is a traditional Vietnamese form of lacquer painting. Created using a toxic lacquer harvested from one region of the country, it requires months of application and sanding back layers of paint to build up the image. Last year, a sơn mài painting sold at auction for $972,000. So what makes these paintings so special? And why are they so expensive? But making this "silk" isn’t easy. Extracting enough lotus silk for one scarf can take two months, and the final product can cost 10 times as much as regular silk. So just how is it made, and what makes it so expensive?