Minerals form in slightly different ways which I will explain
below, however one thing is common about their formation -
is a change in conditions
the surrounding rock, in which the new mineral is more stable than
whatever substance, or another mineral, it was formed from.
plants and animals strive to save energy which is consumed by growth,
movement etc.., rocks and minerals also have an issue with energy and stability.
As you probably know, mineral crystals don't only form but also grow.
And exactly like with animals, it takes them energy to grow.
"want" to spend that energy, they all strive to achieve the total
stability of noble gases (the gases in the last column in the Periodic
Table - He, Ne, Ar, Kr, Xe, and Rn - the gases that never react with
other elements, because they are so stable that they don't need to).
Minerals are obviously
not living things, so why do they grow?
The only reason why mineral crystals grow is that by growing, they get
more stable (even though they use energy while growing). In other
words, the strival for stability drives them to
put on another layer, and another layer, and another layer, because the
larger they are, the less surface they have relative to their volume.
And surface is the unstable part of a mineral.
For exactly the same reason, chemical elements react and minerals form
- the product of the reaction is more stable
The things involved with mineral formation are changing pressures, temperatures, and
often, liquids in
In igenous processes,
the previous rock is first molten into magma, and minerals only form
once the magma cools again when it either gets closer to the surface
(intrusive igneous processes), or erupts out of a volcano (extrusive
igneous processes). In metamorphic
mineral changes happen in solid state - there is no melting. In some
metamorphic processes, only heat is involved (contact metamorphism). In
other, both heat and pressures are involved (regional metamorphism).