Answer:
Most igneous, metamorphic, and sedimentary rocks contain rubidium (Rb) and strontium (Sr) in detectable amounts. However, the concentrations of these elements are almost always less than 1 percent, and they are therefore rarely determined in routine chemical analyses. Neither rubidium nor strontium is a major constituent in the common rock-forming silicate minerals, although strontium does form a carbonate (strontianite) and a sulfate (celestite) which are found in some hydrothermal deposits and certain sedimentary rocks, particularly carbonates.
Explanation: