Science fact: What is the term for mass per unit volume?

Questions

Common name for many rodents belonging to the same family as the woodchuck (marmot), chipmunk, and prairie dog?

Common ore of iron, and one of the most commonly occurring minerals in nature?

Compact, opaque gemstone ranging in color from dark green to almost white?

Company what is the abbreviation for lake minnetonka?

Company what is the former name of the tonka metalcraft company?