'Coltan' is an abbreviation used only in parts of Africa for 'columbo-tantalite', it is a local name or nickname. Mineral concentrates containing tantalum are usually referred to as 'tantalite'. Columbite contains the element columbium, another name for niobium; tantalite contains tantalum.
Tantalite is the mineral or ore, and tantalum is the metallic element which can be extracted (or refined) from the ore. 'Coltan' from central Africa is only a minor source of tantalum.
The main supply of the world's tantalum comes from Australia, where the largest producer operates two mines, and tantalum minerals are also mined in Canada, Brazil, China and Africa. Tantalum is also produced in Thailand and Malaysia as a by-product of tin mining and smelting.
In Africa, tantalum raw materials occur in many regions other than Congo and Rwanda, such as Ethiopia, Nigeria, Zimbabwe, Mozambique, Namibia, South Africa, Egypt. Tantalum-containing concentrates are produced in many of these countries.
A concentrate may contain 10 to 40% Ta2O5, its commercial value is calculated on the tantalum oxide content (which could therefore be as little as one-tenth of the total weight of the material).