What differentiates one mineral group from others? Why are minerals grouped in this manner rather than using their properties?

Minerals are primarily grouped by their chemical composition, in one of the following categories:

Natives - these are single element minerals, like gold and silver. Silicates Oxides Halides Hydroxides Carbonates Sulfides Sulfates Phosphates

Some minerals share the shame chemical composition (polymorphs), so the chemical composition alone is enough to uniquely group them. This is an example of when crystal structure is necessary to group some minerals (examples are the aluminosilicates kyanite, andalusite, and sillimanite).

The properties of minerals are not enough to uniquely separate them into groups, since so many minerals share the same properties. Organization would be very difficult, and it would lead to too many groups. In addition, many minerals have variations in their physical properties, making it even more difficult to accurately group them into a set group. Going further, optical mineralogy opens up a new bucket full of different diagnostic features, further complicating this matter.

Mineral groups are differentiated based on their chemical composition and crystal structure. This classification method is used because minerals within the same group share similar chemical properties and often form under similar conditions, which is useful for understanding their formation and occurrence in nature. Grouping minerals by their properties alone would be less practical because properties can vary widely even among minerals with similar chemical compositions.