Just found a nice working Pioneer PL 550 turntable today. But what the heck does the 'quartz lock' do. And was does the anti-skate knob do as well?
You have to examine it closely with a hand lens. If you can remove individual grains and do a hardness test, so much the better. What kind of rock are you talking about, and just how technical do you want to get with the compositional analysis?
Several ways, depending on your budget and time. 1. Look at the grains with a good hand lens (see answer before). 2. Do a scratch test. Quartz is 7 on the Mohs scale so it should scratch steel and may be a even with glass. 3. Separate the grains of the sedimentary rock into sand-size particals and do some sort of separation process like density liquids (be careful some are harzardous) 4) cut a thin section and look at them through a polarziing light microscope. Any good optical mineralogy textbook will have a list the the characterists that identify quartz. 5) Using the grains from No. 3 use defraction fluids. Refer to Mineralogy text for hints.
