Zambia Exports of granite, porphyry, basalt, sandstone, other monumental or building stone to Namibia was US$554 during 2010, according to the United Nations COMTRADE database on international trade. Zambia Exports of granite, porphyry, basalt, sandstone, other monumental or building stone to Namibia - data, historical chart and statistics - was last updated on May of 2024.