Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Metapelite is an old and currently not widely used field geological term for a clay rich fine-grained clastic sediment or sedimentary rock, i.e. mud or a mudstone
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 Pelos or clay in Greek
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Foliated
Color
Bluish - Grey, Brown, Grey, Light to Dark Grey
Dark Greenish - Grey, Green, Light Green, Light Greenish Grey
Durability
Durable
Durable
Appearance
Vesicular
Banded
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration
As Building Stone, As Facing Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
Cement Manufacture, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
Commemorative Tablets, Creating Artwork
Commemorative Tablets, Creating Artwork
Types
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Metamorphic rock
Features
Host Rock for Lead, Is one of the oldest rock
Easily splits into thin plates, It is One of the Oldest, Strongest and Hardest 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.
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Metapelite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Albite, Chlorite, Quartz
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Aluminium Oxide, CaO, MgO
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
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Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion
Grain Size
Medium to Fine Coarse Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal
Fibrous
Porosity
Less Porous
Highly Porous
Luster
Subvitreous to Dull
Earthy
Specific Gravity
2.86-2.87
3.4-3.7
Transparency
Translucent
Opaque
Density
2.77-2.771 g/cm3
0-300 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Europe
France, Greece, Romania, Scotland, Spain
United Kingdom
Deposits in Western Continents
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Brazil, Colombia, Ecuador
Deposits in Oceania Continent
Australia
New Zealand, South Australia, Western Australia
Central Australia, Western Australia