A quick lesson on earth sciences. Minerals are essentially pure chemical compounds. There are about 3800 officially recognised mineral species.
Rocks are mixtures of minerals.
Granite is a mixture of quartz, microcline, biotite, and some minor minerals like magnetite and titanite. All silicate minerals and the rocks composed of them are safe. Very few silicate minerals are reactive in any way, shape, or form. No one will ever see any that are reactive. These are insoluble and for all practical purposes inert.