Marble.
A metamorphosed limestone. The calcite has recrystallized to form a much prettier rock that is used in statuary. Demonstrate that the rock fizzes with Hydrochloric acid. Because calcite is a soft mineral (hardness of 3 on the Moh's scale), marble is easily carved and consequently has been used for thousands of years in statuary.
A metamorphosed shale. The clay-sized particles of the shale are fused together, creating a much harder rock. The rock also has a planar break, called cleavage (same as for the minerals). This hard material with a planar break was very useful in earlier days for tombstones, roof shingles and other building materials, and is still used under the felt in billiard tables.
In the case of phyllite, higher heat and pressure applied to a slate produces larger crystals. These larger crystals break up the structure of the rock so that it no longer has the planar cleavage; the larger crystals can also give the rock a more shiny appearance.
Schist is basically a slate that has been further metamorphosed. The increased pressure and temperature has allowed crystals to grow and break up the very fine structure typical of slate. These crystals can include garnets and other exotic minerals.
A metamorphosed granite. The pressure and temperature has created a foliated (banded) appearance. Like granite, the color can vary considerably according to the color of whatever minerals make up the rock, The white and pink gneiss in this lab get their colors from different feldspars. Now commonly used as a facing for building interiors.
This was originally a sandstone in which the high heat and pressure haveessentially "welded" the sand grains together. The result is a rock of quartz composition that is very difficult to break. When the rocks does break it typically breaks through the original sand grains, rather than around them as it would with a more poorly cemented sandstone.
Metaconglomerate is like a sandstone but with larger conglomerate-sized grains.
Return to Physical Geology Syllabus
Slate. 
Phyllite. 
Schist. 
Gneiss. (pronounced "nice", but not pronounced that way). 
Quartzite. 
Metaconglomerate.
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