Sir, do you want turquoise or turquoise ornamention?
As I know, if you want to get cheap turquoise, Wuhan would not be your best destination. Shiyan City is better. But from Wuhan to Shiyan, it takes about 7 hours by train.
As for silk, honestly speaking, Wuhan is not the home of silk. Although the silk stores can be found there, most of them are from Hangzhou and Suzhou and other places in Zhejiang or Jiangsu province. In Wuhan, you may go to the area of Jianghan Road to find a silk shop called Suhang Sichou (苏杭丝绸).
Handicrafts can be found in Hanzheng Street. You may go there to shop around.