4.8.1. Unit Rule and Natural Resources.The unit rule, discussed in Section 4.2.2, is often misapplied in the valuation of properties with possible or proven natural resources such as minerals, timber, or oil and gas. For just compensation purposes, property must be valued as a whole—not by summation of its constituent parts.965 Thus, the possible or actual existence of a resource in a property can only be considered to the extent its possible or actual existence would contribute to the market value of the whole property.966 For example, [for] land that is underlaid with marketable minerals, . . . the existence of those minerals is a factor of value to be considered in determining the market value of the property, but the landowner is not entitled to have the surface value of the land and the value of underlying minerals aggregated to determine market value.967 

Indeed, in any given acquisition, it is possible that “the whole property is worth more than, the same as, or even less than the mineral [or other resource] it contains.”968