Subject
photo credits: Wikimedia Commons
An inkstone is traditional Chinese stationery. It is a stone mortar for the grinding and containment of ink. In addition to stone, inkstones are also manufactured from clay, bronze, iron, and porcelain. The device evolved from a rubbing tool used for rubbing dyes dating around 6000 to 7000 years ago. Source: Wikipedia (en)
Subject - wd:Q600794