Definition
Andesite is a dark, fine-grained, brown or greyish intermediate volcanic rock which is a commonly found in lava
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Origin
North America
Romania and Moldova, Europe
Discoverer
Unknown
Unknown
Etymology
From Andes mountains, where it is found in abundance
From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Aphanitic to Porphyritic
Color
Bluish - Grey, Grey, Pink, Yellow
Bluish - Grey, Brown, Grey, Light to Dark Grey
Durability
Durable
Durable
Appearance
Dull and Soft
Vesicular
Interior Uses
Decorative Aggregates, Floor Tiles, Homes, Interior Decoration, Kitchens
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
Office Buildings, Roof Tiles
As Building Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
Cobblestones, Construction Aggregate, for Road Aggregate
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts
Commercial Uses
Commemorative Tablets, Creating Artwork
Commemorative Tablets, Creating Artwork
Types
Icelandite
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Features
Generally rough to touch, High silica content, Is one of the oldest rock
Host Rock for Lead, Is one of the oldest rock
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Middle of the Earth in Ecuador
Not Applicable
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Used
Not Yet Used
Formation
Andesite is a fine-grained igneous rock that forms when the magma is erupted onto the surface and is crystallized quickly.
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.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Ilmenite, Magnetite, Plagioclase, Pyroxene, Zircon
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Compound Content
Silicon Dioxide
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion
Grain Size
Very fine-grained
Medium to Fine Coarse Grained
Fracture
Uneven
Conchoidal
Porosity
Less Porous
Less Porous
Luster
Vitreous
Subvitreous to Dull
Compressive Strength
Not Available
Cleavage
Not Available
Perfect
Toughness
1.1
Not Available
Specific Gravity
2.5-2.8
2.86-2.87
Transparency
Opaque
Translucent
Density
2.11-2.36 g/cm3
2.77-2.771 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
India, Indonesia, Japan, Nepal, South Korea
Not Yet Found
Africa
Egypt, Ethiopia, Morocco, Namibia, South Africa, Tanzania
Not Yet Found
Europe
Austria, Finland, Germany, Italy, Romania, Turkey, United Kingdom
France, Greece, Romania, Scotland, Spain
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Mexico, USA
USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Western Australia
New Zealand, South Australia, Western Australia