Related Clues:

• It may be essential
• Neighbor of Ida.
• It's found in banks
• Furnace fuel
• Comstock output
• Band of gold?
• See 38-Across
• Bauxite or hematite
• Mesabi Range yield
• Change from a krone
• Engine need
• See 57-Down
• It lacks refinement
• See 5-Down
• Some can dig it