The Mimi Moya Eco-Reserve has a typical northern Natal topography with five different habitats spread over the reserve. The different habitats are: Highlands, Riverine, Mist Forest Patches, Savannah and Wetland Patches. The diverse environment plays host to more than 140 species of indigenous trees and shrubs and is the main reason for the exceptional birdlife. The geology is mainly Onverwacht group which forms part of the Barberton Supergroup, which is of particular interest to geologists as it is the oldest known rock formation.

The Onverwacht series outcrops all along the Mkhunyane River (Witrivier). As it is part of one of the oldest rock formations it is of interest to local and overseas universities.

Keen observers will be able to identify a number of geological formations along the riverbed. The name of one of the farmlands included in the reserve – Pypklipberg – refers to the soapstone found here. This was previously used to make smoking pipes.

In the northern part of the reserve, you can find the Mosaan system outcrops. This closely correlates to the Witwatersrand system and has been extensively prospected for gold, which was actively mined on a small scale at a number of localities.