The Sapphire Saw is a tool added by Project Red. It is a saw used to craft blocks from Forge Microblocks. The Saw is used in a workbench with the material to be processed. The Sapphire Saw has a durability of 513 uses, which is half of the Iron Saw from Forge Microblocks.
If the mod MineChem is installed, the Sapphire Saw can be decomposed with the Chemical Decomposer into specific chemical compounds of MineChem.