3. The photo below shows how sandstone can become quartzite and how limestone can become marble. The rock looks dramatically different after metamorphosis. What has happened to the rock on a molecular scale? Hint:look at the crystals. Are the following rock foliated or non-foliated? When extreme heat is added to a Quartz sandstone, you get Quartzite. When extreme heat is added to Limestone, you get Marble. The rock below is a garnet schist. 4. Are garnets more stable deep in the Earth, or on the surface of the Earth? How do you think garnets are formed from what is originally a piece of shale? If you are floating down the Grand Canyon and see garnet schist, what can be determined about the past geologic environment of the area?