Definition
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
  
Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism
  
History
  
  
Origin
Germany
  
England
  
Discoverer
Van Tooren
  
Unknown
  
Etymology
From Greek tephra, ashes from Indo-European base, to burn
  
From Old French esclate, from esclat (French éclat)
  
Class
Igneous Rocks
  
Metamorphic Rocks
  
Sub-Class
Durable Rock, Hard Rock
  
Durable Rock, Medium Hardness Rock
  
Family
  
  
Group
Volcanic
  
Not Applicable
  
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Aphanitic to Porphyritic
  
Foliated
  
Color
Black, Brown, Colourless, Green, Grey, White
  
Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
Yes
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
No
  
Yes
  
Wind Resistant
Yes
  
No
  
Acid Resistant
No
  
No
  
Appearance
Vesicular
  
Dull
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
  
Bathrooms, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads
  
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
  
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
  
Other Architectural Uses
Curbing
  
Curbing
  
Industry
  
  
Construction Industry
Landscaping
  
As Dimension Stone
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Sculpture
  
Artifacts, Monuments, Sculpture, Small Figurines
  
Other Uses
  
  
Commercial Uses
Production of Lime, Soil Conditioner
  
Blackboards, Commemorative Tablets, Laboratory bench tops, Standard material for the bed of Billiard table, Standard material for the beds of Pool and Snooker table, Tombstones, Used in aquariums, Writing Slates
  
Types
Not Available
  
Not Available
  
Features
Host Rock for Lead
  
Easily splits into thin plates, Surfaces are often shiny, Very fine grained rock
  
Archaeological Significance
  
  
Monuments
Not Yet Used
  
Used
  
Famous Monuments
Not Applicable
  
Data Not Available
  
Sculpture
Used
  
Used
  
Famous Sculptures
Data Not Available
  
Data Not Available
  
Pictographs
Not Used
  
Used
  
Petroglyphs
Not Used
  
Used
  
Figurines
Used
  
Used
  
Fossils
Absent
  
Absent
  
Formation
Tephrite 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.
  
Slate is a low grade metamorphic rock that is generally formed by metamorphosis of mudstone or shale, under relatively low pressure and temperature conditions.
  
Composition
  
  
Mineral Content
Alkali feldspar, Nepheline, Plagioclase, Pyroxene
  
Apatite, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon
  
Compound Content
CaO, Carbon Dioxide, MgO, Silicon Dioxide
  
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
  
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, Sea Erosion, Water Erosion
  
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
  
Physical Properties
  
  
Hardness
6.5
  
3-4
  
Grain Size
Medium to Fine Coarse Grained
  
Very fine-grained
  
Fracture
Uneven
  
Splintery
  
Streak
Bluish Black
  
Light to dark brown
  
Porosity
Very Less Porous
  
Less Porous
  
Luster
Subvitreous to Dull
  
Dull
  
Compressive Strength
90.00 N/mm2
  
22
30.00 N/mm2
  
30
Cleavage
Crenulation and Pervasive
  
Slaty
  
Toughness
2.4
  
1.2
  
Specific Gravity
2.86
  
2.65-2.8
  
Transparency
Opaque
  
Opaque
  
Density
2.8-2.9 g/cm3
  
2.6-2.8 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
0.92 kJ/Kg K
  
10
0.76 kJ/Kg K
  
17
Resistance
Heat Resistant, Impact Resistant
  
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
  
Deposits in Eastern Continents
  
  
Asia
Not Yet Found
  
China, India, Turkey
  
Africa
Namibia, Uganda
  
Not Yet Found
  
Europe
Germany, Hungary, Italy, Portugal, Spain
  
Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom
  
Others
Not Yet Found
  
Arctic
  
Deposits in Western Continents
  
  
North America
USA
  
USA
  
South America
Not Yet Found
  
Brazil
  
Deposits in Oceania Continent
  
  
Australia
New Zealand, Western Australia
  
Not Yet Found
  
All about Tephrite and Slate Properties
Know all about Tephrite and Slate properties here. All properties of rocks are important as they define the type of rock and its application. Tephrite belongs to Igneous Rocks while Slate belongs to Metamorphic Rocks.Texture of Tephrite is Aphanitic to Porphyritic whereas that of Slate is Foliated. Tephrite appears Vesicular and Slate appears Dull. The luster of Tephrite is subvitreous to dull while that of Slate is dull. Tephrite is available in black, brown, colourless, green, grey, white colors whereas Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors. The commercial uses of Tephrite are production of lime, soil conditioner and that of Slate are blackboards, commemorative tablets, laboratory bench tops, standard material for the bed of billiard table, standard material for the beds of pool and snooker table, tombstones, used in aquariums, writing slates.