Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Origin
Romania and Moldova, Europe
USA
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 pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Group
Volcanic
Not Applicable
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Quench
Color
Bluish - Grey, Brown, Grey, Light to Dark Grey
Black, Brown, Colourless, Green, Grey, Pink, White
Durability
Durable
Durable
Appearance
Vesicular
Dull and Soft
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts, Monuments
Commercial Uses
Commemorative Tablets, Creating Artwork
Creating Artwork, Gemstone
Types
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Not Available
Features
Host Rock for Lead, Is one of the oldest rock
Host Rock for Lead
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Sculpture
Not Yet Used
Not Yet Used
Famous Sculptures
Not Applicable
Not Applicable
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Not Yet Used
Not Yet Used
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. Pseudotachylite 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
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Not Applicable
Types of Erosion
Chemical Erosion
Not Applicable
Grain Size
Medium to Fine Coarse Grained
Very fine-grained
Fracture
Conchoidal
Uneven
Streak
White
Light to dark brown
Porosity
Less Porous
Less Porous
Luster
Subvitreous to Dull
Vitreous
Compressive Strength
Not Available
Cleavage
Perfect
Irregular
Toughness
Not Available
Not Available
Specific Gravity
2.86-2.87
2.46-2.86
Transparency
Translucent
Transparent to Translucent
Density
2.77-2.771 g/cm3
2.7-2.9 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Not Yet Found
South Korea
Africa
Not Yet Found
Western Africa
Europe
France, Greece, Romania, Scotland, Spain
Great Britain, Switzerland
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
USA
Not Yet Found
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Not Yet Found
Deposits in Oceania Continent
Australia
New Zealand, South Australia, Western Australia
Central Australia, Western Australia
All about Dacite and Pseudotachylite Properties
Know all about Dacite and Pseudotachylite properties here. All properties of rocks are important as they define the type of rock and its application. Dacite belongs to Igneous Rocks while Pseudotachylite belongs to Metamorphic Rocks.Texture of Dacite is Aphanitic to Porphyritic whereas that of Pseudotachylite is Quench. Dacite appears Vesicular and Pseudotachylite appears Dull and Soft. The luster of Dacite is subvitreous to dull while that of Pseudotachylite is vitreous. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas Pseudotachylite is available in black, brown, colourless, green, grey, pink, white colors. The commercial uses of Dacite are commemorative tablets, creating artwork and that of Pseudotachylite are creating artwork, gemstone.