Shale

Shale is fine grained, clastic sedimentary.Shale is a fine-grained sedimentary rock that forms from the compaction of silt and clay-size mineral particles that we commonly call Mud. This composition places shale in a category of sedimentary rocks known as mudstone. Shale is distinguished from other mudstones because it is fissile and laminated. Laminated means that the rock is made up of many thin layers. Fissile means that the rock readily splits into thin pieces along the laminations.

• ·      Composed of mud, mixed of flake of clay mineral, tiny fragment (Silt size particles) of mineral quartz, calcite.
• ·      Texture is fissility

Color is gray

• ·      Red (contained ferric oxide, hematite)
• ·      Brown (contained iron hydroxide, goethite)
• ·      Yellow (contained iron hydroxide, limonite)
• ·      Green (contained micaceous minerals, chlorite, biotite and illite

*** Shale contain heavy metal such as Uranium, Molybdenum, Vanadium, Zinc…

Note: 

• ·      Shale ≠ Mudstone in texture (Fissile and non-fissile) and grain size, but same mineral composite
• ·      Shale ≠ Siltstone in mineral composite (Clay contain and less clay), but same grain size

Uses of Shale

Some shales have special properties that make them important resources. Black shales contain organic material that sometimes breaks down to form natural gas or oil. Other shales can be crushed and mixed with water to produce clays that can be made into a variety of useful objects.