Possible Clues:

• Transparent gem
• Stone — rock perhaps describing one
• Perhaps I carved jewel
• Blue
• A gem may be gleaned from his paper
• County's housing application, in stone
• In one part of the country there's a very soft sort of stone
• Stone Age pottery, possibly first pieces found in county
• Mobile accessory in county is precious item
• Hard mineral perhaps unexpectedly cracked open by one