Definition
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
Discoverer
Van Tooren
Unknown
Etymology
From Greek tephra, ashes from Indo-European base, to burn
From old English cealc chalk, lime, plaster; pebble, from Greek khalix small pebble, in English transferred to the opaque, white, soft limestone
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
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
Clastic or Non-Clastic
Color
Black, Brown, Colourless, Green, Grey, White
Grey, White, Yellow
Durability
Durable
Durable
Appearance
Vesicular
Soft
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Powder
Construction Industry
Landscaping
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, raw material for manufacture of quicklime and slaked lime, Source of calcium
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Sculpture
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Production of Lime, Soil Conditioner
Alumina Refineries, Creating Artwork, Drawing on blackboards, Gymnasts, athletes and mountain climbers use for grip, In aquifers, Paper Industry, Production of Lime, Raw material for manufacture of quicklime, slaked lime, Soil Conditioner, Whiting, Whiting material in toothpaste, paint and paper
Types
Not Available
Not Available
Features
Host Rock for Lead
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
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.
Chalk is formed from lime mud, which accumulates on the sea floor which is then transformed into rock by geological processes.
Mineral Content
Alkali feldspar, Nepheline, Plagioclase, Pyroxene
Calcite, Clay, Clay Minerals, Quartz, Sand
Compound Content
CaO, Carbon Dioxide, MgO, Silicon Dioxide
Ca, NaCl, CaO
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Not Applicable
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
Grain Size
Medium to Fine Coarse Grained
Very fine-grained
Fracture
Uneven
Not Available
Streak
Bluish Black
White
Porosity
Very Less Porous
Highly Porous
Luster
Subvitreous to Dull
Dull
Compressive Strength
Not Available
Cleavage
Crenulation and Pervasive
Non-Existent
Specific Gravity
2.86
2.3-2.4
Transparency
Opaque
Opaque
Density
2.8-2.9 g/cm3
2.49-2.50 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Not Yet Found
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
Africa
Namibia, Uganda
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
Europe
Germany, Hungary, Italy, Portugal, Spain
England, France, Germany, Spain, United Kingdom
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
USA
Canada, USA
South America
Not Yet Found
Colombia
Deposits in Oceania Continent
Australia
New Zealand, Western Australia
Adelaide, New Zealand, Queensland, Tonga, Victoria, Yorke Peninsula
All about Tephrite and Chalk Properties
Know all about Tephrite and Chalk properties here. All properties of rocks are important as they define the type of rock and its application. Tephrite belongs to Igneous Rocks while Chalk belongs to Sedimentary Rocks.Texture of Tephrite is Aphanitic to Porphyritic whereas that of Chalk is Clastic or Non-Clastic. Tephrite appears Vesicular and Chalk appears Soft. The luster of Tephrite is subvitreous to dull while that of Chalk is dull. Tephrite is available in black, brown, colourless, green, grey, white colors whereas Chalk is available in grey, white, yellow colors. The commercial uses of Tephrite are production of lime, soil conditioner and that of Chalk are alumina refineries, creating artwork, drawing on blackboards, gymnasts, athletes and mountain climbers use for grip, in aquifers, paper industry, production of lime, raw material for manufacture of quicklime, slaked lime, soil conditioner, whiting, whiting material in toothpaste, paint and paper.