Investigation of serpentine minerals from metaserpentinized ultramafic rocks in two Archaean green-stone belts, east of Kalgoorlie, has indicated that antigorite, exhibiting a very wide range of textures in thin section, is the dominant serpentine species; however, it is locally accompanied by relict lizardite. Chrysotile occurs both in late tectonic veins and as a present-day weathering product of relict olivine. Analytical data and structural formulae on seven serpentines, characterized independently by X-ray diffraction analysis, support the chemical differences between antigorite and chrysotile postulated by earlier workers.