Definition
Trachyte is a grey fine-grained volcanic rock which mainly consists of alkali feldspar
Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation
Discoverer
Alexandre Brongniart and René Just Haüy
Unknown
Etymology
From Greek trakhus rough’ or trakhutēs roughness
From French schiste, Greek skhistos i.e. split
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Group
Volcanic
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Foliated, Platy
Color
Black, Brown, Dark Greenish - Grey, Green, Grey, Light to Dark Grey, White
Black, Blue, Brown, Dark Brown, Green, Grey, Silver
Durability
Durable
Durable
Appearance
Banded
Layered and Shiny
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Decorative Aggregates, Floor Tiles, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Not Yet Used
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Manufacture of Magnesium and Dolomite Refractories
As Dimension Stone, Building houses or walls, Cement Manufacture, for Road Aggregate, Roadstone
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts
Commercial Uses
Cemetery Markers, Creating Artwork
Used in aquariums, Writing Slates
Types
Not Available
Mica Schists, Calc-Silicate Schists, Graphite Schists, Blueschists, Whiteschists, Greenschists, Hornblende Schist, Talc Schist, Chlorite Schist, Garnet Schist, Glaucophane schist.
Features
Available in Lots of Colors and Patterns, Is one of the oldest rock, Matrix variable
Easily splits into thin plates, Smooth to touch
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Data Not Available
Not Applicable
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Figurines
Used
Not Yet Used
Formation
Trachyte is an igneous volcanic rock with an aphanitic to porphyritic texture. It is the volcanic equivalent of syenite rock and forms as a result of magmatic differentiation.
Schist formed by dynamic metamorphism at high temperatures and pressures that aligns the grains of mica, hornblende and other elongated minerals into thin layers.
Mineral Content
Augite, Biotite, Feldspar, Hornblade, Plagioclase, Quartz
Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Sillimanite, Staurolite, Talc
Compound Content
Potassium Oxide, Sodium Oxide, Silicon Dioxide
CaO, Carbon Dioxide, MgO
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Regional Metamorphism
Not Applicable
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Not Available
Conchoidal
Porosity
Less Porous
Highly Porous
Compressive Strength
Not Available
Cleavage
Not Available
Slaty
Toughness
Not Available
1.5
Specific Gravity
2.7
2.5-2.9
Transparency
Opaque
Opaque
Density
2.43-2.45 g/cm3
2.8-2.9 g/cm3
Resistance
Heat Resistant, Impact Resistant, Wear Resistant
Impact Resistant, Pressure Resistant, Water Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Egypt, Ethiopia, Morocco, Nigeria, South Africa
Europe
Bulgaria, England, Germany, Norway, Romania, Switzerland
Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
USA
Canada, Costa Rica, Cuba, Mexico, Panama, USA
South America
Brazil, Chile
Brazil, Colombia, Guyana
Deposits in Oceania Continent
Australia
New Zealand, Queensland, South Australia, Western Australia
New South Wales, New Zealand, Queensland