Final answer:
The presence of a talc-like material on the hands during a soil texture "feel" assessment indicates the presence of clay, as its fine silt particles give it the characteristic plasticity and cohesiveness.
Step-by-step explanation:
When performing a "feel" assessment of soil texture, the presence of talc-like material on the hands indicates that an appreciable amount of clay is present. The earth's crust undergoes various processes to form a layer of topsoil, which includes deposits of rock and clay. The fine particles of silt in the clay are responsible for its plasticity, and these silt particles consist of minerals such as feldspar, silica, and alkalis. Feldspar, the most abundant mineral on earth, along with the other components, contributes to the clay's texture and properties. When you feel a talc-like substance during the assessment, it is an indicator of the presence of clay because of its fine particles and cohesive nature once water is added.