Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Pyrolite is an igneous rock consisting of about three parts of peridotite and one part of basalt
Origin
Romania and Moldova, Europe
Pike County, U.S
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 the chemical and mineralogical composition of the upper mantle of the Earth
Class
Igneous Rocks
Igneous 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, Opaque Rock
Texture
Aphanitic to Porphyritic
Phaneritic
Color
Bluish - Grey, Brown, Grey, Light to Dark Grey
Dark Greenish - Grey
Durability
Durable
Durable
Appearance
Vesicular
Rough and Shiny
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, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
As Dimension Stone, Cobblestones
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture
Commercial Uses
Commemorative Tablets, Creating Artwork
Creating Artwork, Gemstone, Jewelry, Source of Chromite, Platinum, Nickel and Garnet, Source of Diamonds
Types
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Dunite, Wehrlite, Harzburgite, Lherzolite
Features
Host Rock for Lead, Is one of the oldest rock
Constitutes upper part of the Earth's mantle, Generally rough to touch, Is one of the oldest rock
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Figurines
Not Yet Used
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.
Pyrolite 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.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Amphibole, Chromite, Garnet, Magnesium, Olivine, Phlogopite, Plagioclase, Pyroxene
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Ca, Fe, Mg, Potassium, Silicon Dioxide, Sodium, Titanium Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Medium to Fine Coarse Grained
Coarse Grained
Fracture
Conchoidal
Irregular
Porosity
Less Porous
Less Porous
Luster
Subvitreous to Dull
Shiny
Compressive Strength
Not Available
Cleavage
Perfect
Imperfect
Toughness
Not Available
2.1
Specific Gravity
2.86-2.87
3-3.01
Transparency
Translucent
Translucent to Opaque
Density
2.77-2.771 g/cm3
3.1-3.4 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Not Yet Found
China, India, Indonesia, Kazakhstan, Russia, South Korea, Thailand, Turkey
Africa
Not Yet Found
Morocco, South Africa
Europe
France, Greece, Romania, Scotland, Spain
Finland, France, Georgia, Germany, Great Britain, Italy, Kazakhstan, Netherlands, Norway, Spain, Switzerland, Venezuela
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
USA
Canada, USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Brazil
Deposits in Oceania Continent
Australia
New Zealand, South Australia, Western Australia
New Zealand, Western Australia