Possible Clues:

• City in revolt claiming this writer's flipping abrasive
• Light solidified lava
• Abrasive having advantage over the timid?
• One of The Stones' Gospel music loses gloss
• This person's about to enter a shade abrasive
• A light form of lava often used as an abrasive
• Light, porous volcanic rock
• Light form of solidified lava
• Smoother on a horse, contrary timid creatures
• I'm about to be covered in purple volcanic stone