Raw silk, Silk cocoon and Silk waste are exempted from tax.
Other silk items are taxed at 5%, with full Input tax credit, however refund of excess ITC is not available.
Exempted from tax:
1. Silkworm laying, cocoon 
2. Raw silk 
3. Silk waste 
Taxed at 5% with full ITC (No refund):
1. Silk yarn [5004, 5005, 5006]
2. Woven fabrics of silk or silk waste  [With no refund of ITC accumulation]