Sandawana mines

Emeralds were first discovered there in 1956, at what is now the Vulcan mine site, and the following year at the Zeus mine site. Production began in 1958,^[3] and in 1959 the properties were sold to a Rio Tinto subsidiary Rio Tinto Zinc (RTZ).^[1] The mines were first worked by filling a wheelbarrow with the gem containing soil and then washing away the earth,^[4] but were replaced by modern placer techniques.

In 1993 Rio Tinto sold the mines to a newly formed company, Sandawana Mines (Pvt.) Ltd., where the Zimbabwean government held a significant share.^[1] The mines were closed seven years later due to the drop in demand for emeralds.^[5] But interest in the properties resumed as the price of lithium soared. In 2019, Kuvimba Mining House (KMH), which is 65% owned by the Zimbabwe government, took over the asset.^[2]

Illegal mining takes place at the Sandawana mines due to lax or bribed security.^[2] The global rise in lithium prices in the early 2020s triggered a lithium rush which caused conflicts, leading to the eviction of local people from lithium-rich lands. In Sandawana, the evictions – which were filmed and did the rounds of social media – triggered widespread condemnation of the government.^[6]

The Mweza greenstone belt consists of a series of intensely deformed and moderately metamorphosed ultramafic-to-mafic volcanic rocks and metamorphosed sedimentary rocks.^[7] Intruded into the greenstone are granitic pegmatites containing rare earth minerals such as spodumene. These pegmatite were intruded just prior to and/or during a main deformation event at 2.6 Ga.(2.6 billion years ago).^[8] Subsequently, along the cracks between the pegmatites and the greenstone, a hydrothermal solution complex was injected containing large amounts of sodium, as well as lithium, fluorine, beryllium, phosphorus and chromium.^[9] This solution reacted with the minerals of both the granite pegmatite and the greenstone to produce a variety of uncommon minerals, including emeralds (beryl).^[9]