Soil nutrient levels are important to the health of the soil and how plants are able to use the minerals. If the mineral level is way off, your plants may not be able to use all of the minerals in the soil, even if they are present.
If you plan to amend your soil using minerals/stone, you must test your soil before adding certain trace elements. If you over do it with certain minerals, you will wind up with very poor results. IMPORTANT: Many trace element dust particles are hazardous. Please use extreme caution if you intend to do this yourself!
The Bionutrient Food Association has an extensive list of amendment suppliers and bio-inoculant providers.