#gate #geology #mineralogy
Minerals are composed of atoms or ions that occupy structural sites in a crystal structure.

Different ions can occupy the same structural site if they have similar size, have similar charge and are available in the environment in which the mineral is forming.
This process of one ion replacing another ion is called substitution.

In mineral formulas, ions that commonly substitute for one another are generally placed within a single set of parentheses.
In the olivine group, iron and magnesium can freely substitute for one another in the six - fold, octahedral site. As a result, the formula for olivine is commonly written as (Mg,Fe) 2 SiO 4 .

Telegram Group
https://t.me/+VOV8DwQ6le6IIPqp

Download the App now
http://uwcsj.on-app.in/app/home/app/h...