There isn't really a definitive "four" major rock-forming minerals. Instead, there are eight minerals that are considered the most common and important in forming rocks. They are known as the "rock-forming minerals" or "common minerals":

1. Quartz (SiO2)

2. Feldspar (various, mainly NaAlSi3O8, KAlSi3O8, and CaAl2Si2O8)

3. Mica (various, mainly muscovite and biotite)

4. Amphibole (various, mainly hornblende)

5. Pyroxene (various, mainly augite)

6. Olivine ((Mg,Fe)2SiO4)

7. Calcite (CaCO3)

8. Clay minerals (various)

These minerals make up the majority of Earth's crust and are found in various combinations, giving rise to different rock types.

It's important to note that while these are the most common, there are many other minerals that can be present in rocks, though in smaller amounts.