Continue writing the following text: '' well , you have a keen eye and i 'm happy to see that you have been paying attention in my class . it looks like quartz to me , but let 's check the specific gravity and hardness to be certain . '' matt watched as mr. swartz carefully weighed the sample and measured its displacement in water . then he scratch tested it to determine the hardness . '' alright , with a specific gravity of 2.62 , and hardness of 7 , it 's definitely
quartz