* Compounds are formed when two or more elements chemically combine in a fixed ratio. For example, water (H₂O) is a compound made of hydrogen and oxygen.

* Mixtures are combinations of two or more substances that are not chemically bonded. The substances in a mixture retain their individual properties.

Stones are made up of various minerals, which are themselves compounds. However, the minerals in a stone are not combined in a fixed ratio, and they can vary depending on the specific type of stone.

Examples:

* Granite: A mixture of quartz, feldspar, and mica.

* Limestone: Primarily made of calcium carbonate, but can also contain other minerals.

Therefore, while the individual minerals within a stone are compounds, the stone itself is a mixture of these minerals.