The term 'Ancient Stone' can be broken down into two crossword solutions: Eolith (6 letters) and Rosetta (7 letters). An eolith is a primitive stone tool, believed to have been made by early humans during the Paleolithic period. The Rosetta Stone is an ancient Egyptian artifact, inscribed with a decree from Ptolemy V in 196 BC. It was discovered in 1799 and is now housed in the British Museum.