Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Rhyodacite is an extrusive volcanic rock intermediate in composition between dacite and rhyolite
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
Rhyo lite + dacite : a rock intermediate between rhyolite and dacite that is the extrusive equivalent of granodiorite
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
Fine Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Earthy
Color
Bluish - Grey, Brown, Grey, Light to Dark Grey
Black to Grey, Dark Greenish - Grey
Durability
Durable
Durable
Appearance
Vesicular
Skeletal
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration
As Building Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
Commemorative Tablets, Creating Artwork
Cemetery Markers, Creating Artwork
Types
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Not Available
Features
Host Rock for Lead, Is one of the oldest rock
Available in Lots of Colors and Patterns
Archaeological Significance
Monuments
Not Yet Used
Not Yet Used
Famous Monuments
Not Applicable
Not Applicable
Sculpture
Not Yet Used
Not Yet Used
Famous Sculptures
Not Applicable
Not Applicable
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.
Rhyodacite 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, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Ca, Fe, Potassium Oxide, NA, Potassium, Silicon 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
Grain Size
Medium to Fine Coarse Grained
Fine Grained
Fracture
Conchoidal
Conchoidal
Porosity
Less Porous
Less Porous
Luster
Subvitreous to Dull
Greasy to Dull
Compressive Strength
Not Available
Cleavage
Perfect
Not Available
Toughness
Not Available
2.1
Specific Gravity
2.86-2.87
2.34-2.40
Transparency
Translucent
Opaque
Density
2.77-2.771 g/cm3
Not Available
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Not Yet Found
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
Africa
Not Yet Found
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Europe
France, Greece, Romania, Scotland, Spain
Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland
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
Not Yet Found
Deposits in Oceania Continent
Australia
New Zealand, South Australia, Western Australia
Not Yet Found