Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
Origin
Romania and Moldova, Europe
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Discoverer
Unknown
Unknown
Etymology
From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described
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, Soft Rock
Durable Rock, Soft Rock
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Clastic or Non-Clastic
Color
Bluish - Grey, Brown, Grey, Light to Dark Grey
Grey, White, Yellow
Durability
Durable
Durable
Appearance
Vesicular
Soft
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Powder
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, 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
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Commemorative Tablets, 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
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Chalk Marl and Marl
Features
Host Rock for Lead, Is one of the oldest rock
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
Archaeological Significance
Formation
Dacitic magma is formed by the subduction of young oceanic crust under a thick felsic continental plate. Further, the Oceanic crust is hydrothermally altered as quartz and sodium are added.
Chalk is formed from lime mud, which accumulates on the sea floor which is then transformed into rock by geological processes.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Calcite, Clay, Clay Minerals, Quartz, Sand
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Ca, NaCl, CaO
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
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Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
Grain Size
Medium to Fine Coarse Grained
Very fine-grained
Porosity
Less Porous
Highly Porous
Luster
Subvitreous to Dull
Dull
Specific Gravity
2.86-2.87
2.3-2.4
Transparency
Translucent
Opaque
Density
2.77-2.771 g/cm3
2.49-2.50 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
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Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
Africa
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Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
Europe
France, Greece, Romania, Scotland, Spain
England, France, Germany, Spain, United Kingdom
Deposits in Western Continents
North America
USA
Canada, USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Colombia
Deposits in Oceania Continent
Australia
New Zealand, South Australia, Western Australia
Adelaide, New Zealand, Queensland, Victoria, Yorke Peninsula
All about Dacite and Chalk Properties
Know all about Dacite and Chalk properties here. All properties of rocks are important as they define the type of rock and its application. Dacite belongs to Igneous Rocks while Chalk belongs to Sedimentary Rocks.Texture of Dacite is Aphanitic to Porphyritic whereas that of Chalk is Clastic or Non-Clastic. Dacite appears Vesicular and Chalk appears Soft. The luster of Dacite is subvitreous to dull while that of Chalk is dull. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas Chalk is available in grey, white, yellow colors. The commercial uses of Dacite are commemorative tablets, 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.