Lithium - Lithium is produced from both brines and hard-rock sources (pegmatites). Estimates from 2015 put global lithium production from conventional hard-rock mining of lithium minerals as high as 44% (source: Macquarie research 2016). Lithium pegmatites are a viable source of the metal because of their high concentration in the ores relative to brines, and production from these deposits mitigates global concerns about dependence on supplies from dominant brine producers in Chile and Argentina. Chemical-grade lithium refers to spodumene that is converted to lithium carbonate or lithium hydroxide. Pegmatites are a source of technical-grade lithium, where spodumene is used directly in the ceramics or glass industries without processing.
Tantalum - 70% of global tantalum supply is used in the electronics industry; smart phones and other modern "essentials". Global tantalum supply, which was formerly dominated by production out of Australia, is now dominated by production out of Central Africa, particularly Democratic Republic of Congo. This tantalum has been sold by illegal militias implicated in human rights abuses to fund civil war. The U.S. government signed the Financial Stability Act into law in 2010 to stem the trade of "conflict tantalum," and a system that includes mineral chemistry, geochronology, and mineral liberation analysis is being developed to trace the origin of tantalum ore.