Definition
Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles
  
Rhyodacite is an extrusive volcanic rock intermediate in composition between dacite and rhyolite
  
History
  
  
Origin
Unknown
  
USA
  
Discoverer
Unknown
  
Unknown
  
Etymology
From German Schalstein laminated limestone, and Schalgebirge layer of stone in stratified rock. From Old English scealu in its base sense of- thing that divides or separate,
  
Rhyo lite + dacite : a rock intermediate between rhyolite and dacite that is the extrusive equivalent of granodiorite
  
Class
Sedimentary Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Medium Hardness Rock
  
Durable Rock, Medium Hardness Rock
  
Family
  
  
Group
Not Applicable
  
Volcanic
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Clastic, Splintery
  
Earthy
  
Color
Black, Brown, Buff, Green, Grey, Red, Yellow
  
Black to Grey, Dark Greenish - Grey
  
Maintenance
More
  
More
  
Durability
Durable
  
Durable
  
Water Resistant
No
  
Yes
  
Scratch Resistant
No
  
Yes
  
Stain Resistant
No
  
No
  
Wind Resistant
No
  
No
  
Acid Resistant
No
  
No
  
Appearance
Muddy
  
Skeletal
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
  
Decorative Aggregates, Interior Decoration
  
Exterior Uses
As Building Stone, As Facing Stone, Office Buildings
  
As Building Stone, Garden Decoration
  
Other Architectural Uses
Curbing
  
Curbing
  
Industry
  
  
Construction Industry
Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
  
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Sculpture
  
Artifacts
  
Other Uses
  
  
Commercial Uses
Creating Artwork, Pottery
  
Cemetery Markers, Creating Artwork
  
Types
Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale
  
Not Available
  
Features
Easily splits into thin plates, Generally rough to touch, Very fine grained rock
  
Available in Lots of Colors and Patterns
  
Archaeological Significance
  
  
Monuments
Used
  
Not Yet Used
  
Famous Monuments
Jantar Mantar in India
  
Not Applicable
  
Sculpture
Used
  
Not Yet Used
  
Famous Sculptures
Data Not Available
  
Not Applicable
  
Pictographs
Used
  
Used
  
Petroglyphs
Used
  
Used
  
Figurines
Used
  
Not Yet Used
  
Fossils
Present
  
Absent
  
Formation
Shale forms when very fine-grained clay particles are deposited in water which settle at the bottom of water bodies. They are later compacted hence forming shale.
  
Rhyodacite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
  
Composition
  
  
Mineral Content
Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides
  
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
  
Compound Content
Ca, Fe, Mg, Silicon Dioxide, Sodium
  
Ca, Fe, Potassium Oxide, NA, Potassium, Silicon Dioxide
  
Transformation
  
  
Metamorphism
No
  
Yes
  
Types of Metamorphism
Not Applicable
  
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
Yes
  
Yes
  
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
  
Chemical Erosion, Coastal Erosion, Glacier Erosion
  
Physical Properties
  
  
Hardness
3
  
5.5-6
  
Grain Size
Very fine-grained
  
Fine Grained
  
Fracture
Not Available
  
Conchoidal
  
Streak
White
  
Black
  
Porosity
Highly Porous
  
Less Porous
  
Luster
Dull
  
Greasy to Dull
  
Compressive Strength
95.00 N/mm2
  
20
200.50 N/mm2
  
9
Cleavage
Slaty
  
Not Available
  
Toughness
2.6
  
2.1
  
Specific Gravity
2.2-2.8
  
2.34-2.40
  
Transparency
Opaque
  
Opaque
  
Density
2.4-2.8 g/cm3
  
Not Available
  
Thermal Properties
  
  
Specific Heat Capacity
0.39 kJ/Kg K
  
23
1.12 kJ/Kg K
  
7
Resistance
Heat Resistant, Impact Resistant
  
Heat Resistant
  
Deposits in Eastern Continents
  
  
Asia
Bangladesh, China, India, Russia
  
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
  
Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
  
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
  
Europe
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
  
Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
USA
  
Canada, USA
  
South America
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
  
Not Yet Found
  
Deposits in Oceania Continent
  
  
Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia
  
Not Yet Found