Emeralds have been found at several locations in Zimbabwe (formerly Rhodesia). Note that it is neighbors Zambia, the second largest emerald producer in the world. One important source of superb quality emeralds that are small in size, is the Sandawana mine field.
Zimbabwe emeralds are known for being vivid without needing to be large. Generally speaking bigger is better for colored gems, because the size can help improve the color. Emeralds from Zimbabwe do not need size to display color like ones from Colombia and Brazil, and often grow very small with faceted gems ranging from 2mm-4mm.
Emeralds are Type III gems, which are described as almost always being included and unclear. In comparison to the average clarity of emeralds, the ones from Zimbabwe are noted for being highly included. This makes finding large, gem quality emeralds from this country even less likely than other sources. It is the same reason why such quality gems are not popular on the world market.
Emeralds were not discovered in the country until 1956. Prospectors Laurence Contat and Cornelius Oosthuizen were attracted by the offerings that the Rhodesian government was making at the time to prospectors of metals and gemstones. Within ten days of their arrival to the area and beginning to dig in what they considered the most favorable location full of large pegmatites, the duo found emerald deposits. Seven months later they hit upon a second, much larger, deposit.
In more common terms, these prospectors were so lucky they won the lottery twice in a row.
Unfortunately, the Sandawana mine has been fraught with difficulties from political unrest, to economically unfavorable conditions, to a slow down in supply. There’s still miles of untapped emerald deposits, though whether they are mined or not depends on the political and economic stability of the country.