When procuring raw silica sand, the most critical factor is the SiO2 (Silicon Dioxide) content, which should typically be above 99% for high-end glass or electronic applications. You must also evaluate the Fe2O3 (Iron Oxide) levels, as low iron content (often <0.015%) is essential for optical glass and solar panels. Additionally, specify the grain size distribution (mesh size) to ensure it meets your specific industrial needs, whether for foundry casting, hydraulic fracturing, or glass manufacturing.