Definition
Trachyte is a grey fine-grained volcanic rock which mainly consists of alkali feldspar
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
Discoverer
Alexandre Brongniart and René Just Haüy
Unknown
Etymology
From Greek trakhus rough’ or trakhutēs roughness
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, Medium Hardness Rock
Durable Rock, Soft Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Clastic or Non-Clastic
Color
Black, Brown, Dark Greenish - Grey, Green, Grey, Light to Dark Grey, White
Grey, White, Yellow
Durability
Durable
Durable
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Powder
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, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, raw material for manufacture of quicklime and slaked lime, Source of calcium
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Cemetery Markers, Creating Artwork
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
Felsic volcanic rock
Chalk Marl and Marl
Features
Available in Lots of Colors and Patterns, Is one of the oldest rock, Matrix variable
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
Archaeological Significance
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.
Chalk is formed from lime mud, which accumulates on the sea floor which is then transformed into rock by geological processes.
Mineral Content
Augite, Biotite, Feldspar, Hornblade, Plagioclase, Quartz
Calcite, Clay, Clay Minerals, Quartz, Sand
Compound Content
Potassium Oxide, Sodium Oxide, Silicon Dioxide
Ca, NaCl, CaO
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Regional Metamorphism
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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, Wind Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
Grain Size
Fine Grained
Very fine-grained
Porosity
Less Porous
Highly Porous
Specific Gravity
2.7
2.3-2.4
Transparency
Opaque
Opaque
Density
2.43-2.45 g/cm3
2.49-2.50 g/cm3
Resistance
Heat Resistant, Impact Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
Europe
Bulgaria, England, Germany, Norway, Romania, Switzerland
England, France, Germany, Spain, United Kingdom
Deposits in Western Continents
North America
USA
Canada, USA
South America
Brazil, Chile
Colombia
Deposits in Oceania Continent
Australia
New Zealand, Queensland, South Australia, Western Australia
Adelaide, New Zealand, Queensland, Victoria, Yorke Peninsula
All about Trachyte and Chalk Properties
Know all about Trachyte and Chalk properties here. All properties of rocks are important as they define the type of rock and its application. Trachyte belongs to Igneous Rocks while Chalk belongs to Sedimentary Rocks.Texture of Trachyte is Aphanitic to Porphyritic whereas that of Chalk is Clastic or Non-Clastic. Trachyte appears Banded and Chalk appears Soft. The luster of Trachyte is metallic while that of Chalk is dull. Trachyte is available in black, brown, dark greenish - grey, green, grey, light to dark grey, white colors whereas Chalk is available in grey, white, yellow colors. The commercial uses of Trachyte are cemetery markers, creating artwork 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.