Definition
Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation
  
Rhyolite is a fine-grained igneous rock which is rich in silica
  
History
  
  
Origin
Unknown
  
North America
  
Discoverer
Unknown
  
Ferdinand von Richthofen
  
Etymology
From French schiste, Greek skhistos i.e. split
  
From German Rhyolit, from Greek rhuax lava stream + lithos stone
  
Class
Metamorphic Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Medium Hardness Rock
  
Durable Rock, Hard Rock
  
Family
  
  
Group
Not Applicable
  
Volcanic
  
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
  
Coarse Grained Rock, Opaque Rock
  
Texture
Foliated, Platy
  
Aphanitic, Glassy, Porphyritic
  
Color
Black, Blue, Brown, Dark Brown, Green, Grey, Silver
  
Grey, White, Light Black
  
Maintenance
Less
  
More
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
Yes
  
Scratch Resistant
No
  
Yes
  
Stain Resistant
No
  
Yes
  
Wind Resistant
No
  
Yes
  
Acid Resistant
No
  
Yes
  
Appearance
Layered and Shiny
  
Banded
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Floor Tiles, Interior Decoration
  
Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens
  
Exterior Uses
Garden Decoration, Paving Stone
  
As Building Stone, As Facing Stone, Paving Stone, Office Buildings
  
Other Architectural Uses
Not Yet Used
  
Not Yet Used
  
Industry
  
  
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, for Road Aggregate, Roadstone
  
Arrowheads, As Dimension Stone, Building houses or walls, Construction Aggregate, Cutting Tool, for Road Aggregate, Knives
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts
  
Artifacts
  
Other Uses
  
  
Commercial Uses
Used in aquariums, Writing Slates
  
Gemstone, Laboratory bench tops, Jewelry
  
Types
Mica Schists, Calc-Silicate Schists, Graphite Schists, Blueschists, Whiteschists, Greenschists, Hornblende Schist, Talc Schist, Chlorite Schist, Garnet Schist, Glaucophane schist.
  
Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks.
  
Features
Easily splits into thin plates, Smooth to touch
  
Acidic in nature, Available in lots of colors
  
Archaeological Significance
  
  
Monuments
Not Yet Used
  
Not Yet Used
  
Famous Monuments
Not Applicable
  
Not Applicable
  
Sculpture
Not Yet Used
  
Not Yet Used
  
Famous Sculptures
Not Applicable
  
Not Applicable
  
Pictographs
Used
  
Not Used
  
Petroglyphs
Used
  
Not Used
  
Figurines
Not Yet Used
  
Not Yet Used
  
Fossils
Absent
  
Absent
  
Formation
Schist formed by dynamic metamorphism at high temperatures and pressures that aligns the grains of mica, hornblende and other elongated minerals into thin layers.
  
Rhyolite is a felsic extrusive rock and due to its high silica content, rhyolite lava is very viscous and is volcanic equivalent of granite.
  
Composition
  
  
Mineral Content
Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Sillimanite, Staurolite, Talc
  
Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz
  
Compound Content
CaO, Carbon Dioxide, MgO
  
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide, Sodium
  
Transformation
  
  
Metamorphism
No
  
Yes
  
Types of Metamorphism
Not Applicable
  
Burial Metamorphism, Cataclastic 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, Sea Erosion, Water Erosion, Wind Erosion
  
Physical Properties
  
  
Hardness
3.5-4
  
6-7
  
Grain Size
Medium to Fine Coarse Grained
  
Large and Coarse Grained
  
Fracture
Conchoidal
  
Sub-conchoidal
  
Streak
White
  
Colorless
  
Porosity
Highly Porous
  
Highly Porous
  
Luster
Shiny
  
Earthy
  
Compressive Strength
Not Available
  
140.00 N/mm
2
  
15
Cleavage
Slaty
  
Not Available
  
Toughness
1.5
  
2
  
Specific Gravity
2.5-2.9
  
2.65-2.67
  
Transparency
Opaque
  
Opaque
  
Density
2.8-2.9 g/cm3
  
2.4-2.6 g/cm3
  
Thermal Properties
  
  
Resistance
Impact Resistant, Pressure Resistant, Water Resistant
  
Heat Resistant, Wear Resistant
  
Deposits in Eastern Continents
  
  
Asia
Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam
  
China, India
  
Africa
Egypt, Ethiopia, Morocco, Nigeria, South Africa
  
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
  
Europe
Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland
  
Germany, Iceland, Ireland, Italy, Spain
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, Costa Rica, Cuba, Mexico, Panama, USA
  
Canada, USA
  
South America
Brazil, Colombia, Guyana
  
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
  
Deposits in Oceania Continent
  
  
Australia
New South Wales, New Zealand, Queensland
  
New Zealand, Queensland, Western Australia