When evaluating Viscose Nylon (often called Rayon Nylon) blends, the composition ratio is critical; a common high-quality blend is 70% Viscose and 30% Nylon, which balances the softness of viscose with the durability of nylon. You must verify the fabric weight (GSM) to ensure it meets your application needs (e.g., 200-300 GSM for ponte roma or heavier knits). Additionally, check the yarn count (e.g., 30s, 40s) as it determines the fineness and smoothness of the textile. For stretch fabrics, confirm the percentage of Spandex/Elastane if applicable.