Each individual Buddhist sculpture has various characteristics and attributes which art historians use as clues to determine when and where it was made. Sometimes a statue will have an inscription or contain a document which attests to when, where, and who made it. Reliable archaeological records which state where a statue was excavated are also valuable clues for the historian. However, when neither of these sources of information are available, scholars can still glean important information on an individual statue by its style, the particular iconography employed by the artist, physical characteristics such as the material used to make the statue, the percentage of metals used in an alloy, casting and carving techniques, and various other contextual clues.