1. Imagine that you find two milky white crystals, each about 2 cm across. One consists of plagioclase and the other of quartz. How can you determine which is which? 2. Could you use crushed calcite...

1. Imagine that you find two milky white crystals, each about 2 cm across. One consists of plagioclase and the other of quartz. How can you determine which is which?

2. Could you use crushed calcite to grind facets on a diamond? Why or why not?