Shale

Shale Characteristics:
 * shales are soft enough to be scratched with a knife
 * feel smooth and almost greasy to the touch

Shale rock is a type of sedimentary rock formed from clay that is compacted together by pressure.

composed mostly of tiny, clay particles of the kind found in mud, much smaller than sand particles, so shale is smoother than sandstone

what color does it have?
 * black
 * blue
 * gray
 * red
 * greenish
 * 1/2 pink
 * brown

How is shale sorted?
 * shale is well sorted

Interesting facts:
 * usually composed of mica and clay minerals
 * the grains are so fine that the rock seems to have a homogeneous appearance, and individual minerals cannot be identified without the help of a microscope
 * no matter where you break shale it will form a smooth texture
 * shales characteristically consist of at least 30 percent clay minerals and substantial amounts of quartz
 * the hardness can differ

Where is shale found on the earth?
 * shales are often found with layers of sandstone or limestone
 * they typically form in environments where muds or silts were deposited by gentle transporting currents and became compacted
 * the deepest parts of the ocean
 * river floodplains when it washes out
 * hill sides on earths crust

what is shale used for?
 * you can get oil out of it
 * for building walls
 * used for roads
 * profit
 * decorations in front yards