Quiz of the day (3)

I enjoy answering quiz questions. If you are like me, here is a random quiz question of the day in general knowledge for you to answer or else check back tomorrow for the answer. 

What is the hard mineral used in clock?

a) Diamond

b) Gypsum

c) Topaz

d) Quartz 

Quiz of the day (2) Answer: c) Zoophyte (coral, sea anemone)