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
Discoverer
Van Tooren
Abraham Gottlob Werner
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
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, Green, Grey, White
Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Vesicular
Dull
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
Construction Industry
Landscaping
As Dimension Stone
Antiquity Uses
Artifacts, Sculpture
Artifacts, Monuments, Sculpture, Small Figurines
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
Igneous rock
Phyllite, Schist, and Slate
Features
Host Rock for Lead
Easily splits into thin plates, Surfaces are often shiny, Very fine grained rock
Archaeological Significance
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.
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
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
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
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
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
Cleavage
Crenulation and Pervasive
Slaty
Specific Gravity
2.86
2.65-2.8
Transparency
Opaque
Opaque
Density
2.8-2.9 g/cm3
2.6-2.8 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
-
China, India, Turkey
Europe
Germany, Hungary, Italy, Portugal, Spain
Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom
Deposits in Western Continents
Deposits in Oceania Continent
Australia
New Zealand, Western Australia
-
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, 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.