The International Tin Supply Chain Initiative (ITSCI) is an industry-led traceability and due-diligence programme for the so-called 3T minerals (tin, tantalum and tungsten) sourced from the Great Lakes region of Africa. It is operated jointly by the International Tin Association and Pact, an international development NGO, and is the largest such scheme covering the Democratic Republic of the Congo, Rwanda, Burundi and Uganda.

Although ITSCI is not a gem-trade scheme, it is repeatedly cited as a reference framework in coloured-stone responsible-sourcing discussions, and tantalum-bearing pegmatites in the Great Lakes also produce gem tourmaline, beryl and garnet in the same artisanal mine sites covered by the programme. The OECD Due Diligence Guidance for Responsible Supply Chains of Minerals from Conflict-Affected and High-Risk Areas, on which ITSCI was originally built, has in turn shaped the responsible-sourcing protocols of organisations including the Responsible Jewellery Council and the Coloured Gemstones Working Group.

Independent reviews of ITSCI, notably the 2022 assessment by the Responsible Minerals Initiative, found weaknesses in mine-site monitoring and tag handling, and the scheme's coverage was reduced by RMI in subsequent updates. The episode is frequently invoked in trade discussion as an illustration of the difficulty of building defensible chain-of-custody for artisanally mined commodities, a problem common to coloured-stone sourcing.