Silk fabric was first developed in ancient China. And, about 5,000 years ago, China began to cultivate silkworm, and silk production is an inseparable secret. However, the export of cocoons was punishable by death this the 19th century. Silk was the most valuable commodity in China. Today, Thailand, India and even Italy are competing with the Chinese for quality.
Different dyeing and weaving techniques provide a wide variety of silk fabrics and diversity. Therefore, seeing wispy light, translucent fabric next to a heavy brocade coat and some loosely woven warm but feather light scarves is normal.
Every part of the silk is unique. Silk can keep you cool in the heat and warm in the cold. Northern China, Japan and South Korea are very hot in the summer and very cold in winter. Thus, whatever the season, you can wear silk undergarment, for silk material is not only useful but also beautiful.
Light refraction on silk will create a lovely pearl luster. You not only can dye silk but also can paint, print and embroider it. Since China opened up to direct trade with Japan, Japanese nobility would bankrupt for a handcrafted Kimono.
There are different grades of silk. If you want to buy a real silk, you can make a burn test, silk only burns and it will not make good fuel.