Related Clues:

• Top of the Mohs scale
• Area of expertise
•     Specialty
• Catch flies
• This word could follow 25- and 43-Across, 10- and 42-Down
• Sphere of activity
• __ trip
• Kind of mouse
• Red card
• Use leather on a diamond?
• Delaware, the ___ State
• Playing field
• It covers all the bases
• Stone or suit
• One in a red suit