A passion for diamonds drove South African sisters Mathole and Ramodipa to drop their careers as an investment banker and an optometrist. The siblings run one of the few women-owned diamond polishing businesses in the world. And, despite the slumping global market for diamonds, and a shrinking industry in South Africa, they’ve managed to keep shining and developing new female talent. After qualifying as diamond valuators, in 2008 they started a cutting and polishing shop, Kwame Diamonds — the first and only one run by sisters in South Africa. The sisters cut their way into the diamond industry, selling only responsibly sourced, certified stones bought from mining companies operating in South Africa.