### substance | shale:

Black shale
* Some black shale contains minerals
* are deposited in anoxic or low oxygen environments, such as in stagnant water columns.
* contain organic material that sometimes breaks down to form natural gas or oil.
+ Shale, Formation of shale: Sedimentary rocks
  * Black shales are deposited in anoxic or low oxygen environments, such as in stagnant water columns. They are common in some Palaeozoic and Mesozoic strata, Some black shales contain abundant heavy metals such as molybdenum, uranium, vanadium, and zinc. R. Zangerl and E.S. Richardson 1963. Fieldiana Memoirs'  '4', Field Museum of Natural History, Chicago. 352J.D. Vine and E.B. Tourtelot 1970. Geochemistry of black shale deposits - a summary report.

Oil shale
* contains a waxy substance known as kerogen, which yields oil when heated.
* is shale
  - the rock from which shale oil is extract ed
* rock that contains significant amounts of organic material in the form of kerogen.
* sedimentary rock.
* type of sedimentary rock that is rich in kerogen.

### substance:

Slate
* Most slate has smooth surfaces.
* can also have white lines across the paws and throat
  - be of almost any color
* foliated metamorphic rock that is formed through the metamorphism of shale.
* formed from sediment that fell into deep water rich in organic matter is black.
* has a natural roughness unless it is rubbed down to produce a really smooth surface
  - texture
* includes sections.
* is actual stone that splits naturally into thin uniform thicknesses
  - an example of a metamorphic rock
  - fine-grained, relative to granite, and also much more uniform in composition
  - formed by the metamorphsis of usually shale
* is formed from clay-rich mud in response to tectonic stress
  - shale that has been super-heated and compressed
  - when sedimentary rocks are metamorphosed by great pressure
  - ground up into a fine powder and mixed with a tough liquid polymer resin
  - harder and more durable than shale, but breaks easily into thin layers
  - lists
  - located in roofs
  - low-grade metamorphic shale
  - metamorphic a. sandstone
  - mined in the mountains
  - quarried in the United States in Vermont, New York, Pennsylvania and Virginia
  - softer than a knife blade
  - the online magazine of news, politics, and culture
  - used as roofing but also as building material
* is used for flooring and as crushed product
  - roofing and quartzite for flagging
  - in blackboards, talc in talcum power, and soapstone for carving
  - websites
* kind of stone that can be separated into flat sheets.
* metamorphic mudstone or shale.
* metamorphic rock formed from shale under great pressure
  - found in southwestern Vermont
* metamorphic rock that is formed from the sedimentary rock mudstone
  - useful building material
* natural dense solid rock
  - hand crafted product that can have slight variations in texture and thickness
  - product that was formed millions of years ago
  - stone that is nonporous and heat-resistant
* rock formation with one very unique and distinctive characteristic.
* semi-metamorphic rock.
* vary in color, most commonly seen in black, gray, red, purple, or green.
* very fine-grained rock composed mainly of quartz and mica.
* weather-resistant, durable stone that is used for patios and sidewalks.
+ Geology, Types of rock, Metamorphic rock
  * Metamorphic rock is rock that has been changed. Sometimes an igneous, or a sedimentary rock can be heated, or squashed under the ground, so that it changes. Metamorphic rock is often harder than the rock that it was before it changed. One well-known metamorphic rock is marble which is valued for its different colours, and because it can be carved and polished. Slate is a metamorphic rock that is a useful building material.
+ Hunsrück: Rhineland-Palatinate