Related Clues:

• Diamond, for one
• Setting sight
• Peach
• Emerald or pearl
• Great pitching effort, as it were
• Turquoise or topaz, e.g.
• What carats measure
• Topaz or turquoise
• Onyx or opal
• A loupe might be used on it
• Perfect instance
• Prized stone
• Non-specific
• A precious stone
• The senior officer is common and widespread