Related Clues:

• Refinery metal
• Petroleum
• Certain paintings
• Valuable vein
• Chef's bottleful
• Alberta export
• Newfoundland export
• Well output
• Raw metal
• Contents of a lode-bearing wall?
• Quaker State, e.g.
• Source of gold
• Gusher's gush
• Olive __
• It can follow the first word of 17-, 26-, 37-, 50- and 60-Across