Values are affected by impurities. Values given in different sources vary considerably. Those given here are an average if there is no great consensus.
Resistivity is temperature dependent.
See the references for values at other temperatures. In some cases, resistivity depends upon in which direction along a single crystal the measurement is made. The reciprocal of the electrical resistivity is the electrical conductivity. Literature sources G.W.C. Kaye and T.H. Laby in Tables of physical and chemical constants , Longman, London, UK, 15th edition, 1993. A.M. James and M.P. Lord in Macmillan's Chemical and Physical Data , Macmillan, London, UK, 1992.