Possible Clues:

• Church walls in Barcelona perhaps quartz
• Black mineral placed outside a church
• Herb, in charge of a building in Rome
• Important church
• Fawlty in charge of a building in Rome
• Pound I contributed to plain area in big church
• Important church, as St Peter's in Rome
• Roman Catholic church with special privileges
• Old Roman hall
• Herb, one originally cultivated next to a colonnaded hall