Why were common stones traded?
Common stones, such as the ones discussed below, were originally traded for practical, utilitarian reasons. Stones such as obsidian and diorite were imported to Mesopotamia to fill gaps in the material record, and indigenous calcite stones, such as alabaster, were exported to markets farther abroad in exchange for other materials. When metal and ceramics began to replace many of the utilitarian functions of these common stones during the Bronze Age, the emphasis began to shift to the ideological function of the material, rather than practical considerations. Some stones, like diorite, were particularly prized for their dark color and distinctly reserved for royal portraiture. Obsidian was valued for its surface luster and transparency, which had favorable connotations in Mesopotamian religion.