How Minerals Form:

* Crystallization from a melt: Magma (molten rock below the Earth's surface) and lava (molten rock above the Earth's surface) cool and solidify, forming minerals. This is how igneous rocks are formed.

* Precipitation from a solution: Minerals dissolved in water (like salt in ocean water) can precipitate out as the water evaporates or changes temperature. This is how sedimentary rocks are formed.

* Solid-state transformation: Existing minerals can change into new minerals under high pressure and/or temperature, without melting. This is a key process in the formation of metamorphic rocks.

* Biological processes: Some organisms (like shellfish) create minerals as part of their shells or skeletons.

What is NOT a method of mineral formation:

* Erosion: Erosion is the process of breaking down and transporting existing rocks and minerals. It does not create new minerals.

Therefore, the answer to your question is "erosion."