From the geology course I took in 1975: Minerals are naturally occurring crystals of compound. Snow is a mineral, but volcanic glass is not. Rocks are amalgams of minerals and non-minerals.
In corpus linguistics, a collocation is a sequence of words or terms that co-occur more often than would be expected by chance. In phraseology, collocation is a sub-type of phraseme. An example of a phraseological collocation, as propounded by Michael Halliday, is the expression strong tea.
A collocation is two or more words that often go together. These combinations just sound right to native English speakers, who use them all the time. On the other hand, other combinations may be unnatural and just sound wrong.