Izitsha zobumba ezipendiwe zibhekisela esitsheni sobumba esipholishiwe esibomvu-sawolintshi esingenalutho, esiboniswa ngemibala yemvelo yamaminerali, i-ocher ne-manganese oxide njengezakhi zombala, bese zishiswa kuhhavini. Esidumbu esibomvu esisawolintshi siveza iphethini elihle le-ocher ebomvu, emnyama, emhlophe, nemibala ehlukahlukene, eyenza ubumba obunobunye obuphezulu phakathi kwephethini nokuma kwesitsha, nokufeza umphumela wokuhlobisa nobuhle.