The Defenition of A Rock & Mineral
One definition of a minerals is…an inorganic, homogenous solid, with a defined chemical composition, a set crystal structure, and is naturally occurring.
This sounds overwhelming but when it is broken down into simpler terms it is easy to understand.
#1 - A mineral is inorganic. This means it is not made by anything living.
#2 - Homogenous a substance is mixed well, so well you can’t separate its components without changing what it is. A simple example would be fry sauce. Two of the ingredients for fry sauce is mustard and catsup. If you take out either the mustard or catsup it is no longer fry sauce. The opposite of homogenous is heterogeneous. This is when your French fry is in the sauce. You can remove the fry and lick it off keeping just the fry.
#3 - A solid is pretty simple. Being a solid means it is not a liquid or a gas.
$4 - Every mineral has its own distinct chemical composition. If you change that composition by adding or subtracting even one molecule you change the mineral. A good example of this is water. Water has a composition of H2O. If you add an extra oxygen to the chemical formula, it changes the substance completely. H2O2 is poisonous.
#5 - Every mineral forms a crystal. Crystals are put together in the same way Legos snap together. If you have a large bucket of just the square blocks with 4 blips on top and you build something, it will be a square or a form of a square. You don’t have much choice in the matter. Crystals are the same way, they are made up of molecules that are “snapped” together the same way Legos are. The shape of the molecule is expressed in the shape of the crystals.
The last part of the definition is naturally occurring. This means that the mineral formed in nature without any help from humans.
Here is a small and simple test. Tell if the substance listed is a mineral or not and why.
Diamond: Yes, it fits all the components of the definition.
Amber: No, it is petrified tree sap and is therefore organic.
Granite: No, it is heterogeneous.
Ice: It depends. If it is ice from the freezer, then no, that kind of ice is man made. But, a snowflake is a mineral
This is only one recognized definition and there are others. As with every rule there are exceptions.