Possible Clues:

• Pigment made from genuine fish
• Mineral found in non-ersatz fish
• Mineral found in actual fish
• Soft orange-red crystalline mineral, an ore of arsenic
• Mineral contributing to surreal garden
• Mineral not fake guy brought up
• Mineral sometimes called ruby of arsenic
• Mineral water at last needed by a cracking composer
• Mineral in concrete covering over half of growing area
• Mineral that's genuine on raised piece of cloth