Nowadays, there are strong economical, ecological, and social incentives to develop novel green chemicals from renewable resources to reduce the environmental impact of processing. Cellulose, which is the most abundant natural polymeric source, offers one promising green alternative that could replace the present synthetic chemicals. In this study, two types of modified nanocelluloses (amphiphilic and hydrophilic) were produced and tested to understand their ability to function as collectors and depressants in the mineral flotation process for pure hematite and pure quartz. Hydrophilic nanocellulose (called dicarboxylic acid nanocellulose (DCC)) was observed to be a more selective depressant for hematite than for quartz. DCC seems to be most effective at a pH level of 6. Amphiphilic nanocrystalline celluloses (ANCCs) work as collectors. ANCCs were pH-dependent collectors, and they worked well at a pH value of 10 in the case of the investigated oxides (hematite and quartz). This research indicated that nanocelluloses functioned already at least at the same level as a commercial starch depressant for hematite and as an ether amine collector for quartz.