Think ingredient and mixture.
A mineral has a characteristic composition and internal crystal structure. A rock is an aggregate of geological material: it can contain several minerals. A beautiful crystal attached to a rock does not give the whole rock that mineral’s name.
Read the specimen in layers.
The supporting material is often called the matrix. Describe it separately from the crystals you are studying. At Sidi Rahal, quartz geodes in basaltic rock make this distinction especially tangible.
Species, variety, shape.
Quartz is a species. Amethyst is a quartz variety. A geode describes a mineral-lined cavity, not a mineral species. Keeping these words separate makes labels clearer and searches much more useful.