One way to bring the earth into your house if a cob or straw bale style-construction is not an option, is by using lite straw clay.  This process can be used with either new stick-frame construction, or with renovations.  The straw is lightly coated in clay slip, then rammed into wooden forms, which are removed after it dries.  Lite straw clay has an excellent R-value, involves zero pink-fiberglass, zero drywall, and is almost always a building material that can be sourced within a few miles.  The finished walls are great sound barriers and insulators, and they are perfect substrates for beautiful clay and lime plasters.