The answer is 79 I believe
Take a look at this and let me know if you've any doubts further!
Answer:
Metamorphic rocks form from heat and pressure changing the original or parent rock into a completely new rock. The parent rock can be either sedimentary, igneous, or even another metamorphic rock. The word "metamorphic" comes from Greek and means "To Change Form"
Explanation:
Diamond is not a rock it is a mineral.