The δSi value of sediment porewater may be affected by post-depositional (diagenetic) precipitation or dissolution of Si. It is important to understand the extent and isotopic fractionations of these processes, as they alter the δSi values of the originally deposited sediments, and determine the δSi preserved in the rock record. Generally, precipitation of Si prefers the light isotope (Si) and leads to Si-enriched dissolved Si in the hosting solution. The isotopic effect of Si dissolution in porewater is yet to be clear, as some studies report a preference for Si during dissolution, while other studies document that isotopic fractionation was not expressed during dissolution of sediments.