The group or family that never appears in the elements forming mineral compounds is the noble gases.

Here's why:

* Noble gases are in Group 18 of the periodic table.

* They are extremely unreactive due to their full outer electron shells, making them very stable.

* This stability means they rarely form chemical bonds with other elements, and thus are not found in mineral compounds.

While some noble gases (like argon) can be trapped within mineral structures, they are not chemically bonded to the other elements forming the mineral.