Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Andesite is a dark, fine-grained, brown or greyish intermediate volcanic rock which is a commonly found in lava
Origin
Romania and Moldova, Europe
North America
Discoverer
Unknown
Theodor von Gümbel
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 Andes mountains, where it is found in abundance
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Aphanitic to Porphyritic
Color
Bluish - Grey, Brown, Grey, Light to Dark Grey
Bluish - Grey, Grey, Pink, Yellow
Durability
Durable
Durable
Appearance
Vesicular
Dull and Soft
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Floor Tiles, Homes, Interior Decoration, Kitchens
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration
Office Buildings, Roof Tiles
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
Cobblestones, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Commemorative Tablets, Creating Artwork
Commemorative Tablets, Creating Artwork
Types
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Icelandite
Features
Host Rock for Lead, Is one of the oldest rock
Generally rough to touch, High silica content, Is one of the oldest rock
Archaeological Significance
Famous Monuments
-
Middle of the Earth in Ecuador
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.
Andesite is a fine-grained igneous rock that forms when the magma is erupted onto the surface and is crystallized quickly.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Ilmenite, Magnetite, Plagioclase, Pyroxene, Zircon
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
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
Very fine-grained
Fracture
Conchoidal
Uneven
Porosity
Less Porous
Less Porous
Luster
Subvitreous to Dull
Vitreous
Specific Gravity
2.86-2.87
2.5-2.8
Transparency
Translucent
Opaque
Density
2.77-2.771 g/cm3
2.11-2.36 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
-
India, Indonesia, Japan, Nepal, South Korea
Africa
-
Egypt, Ethiopia, Morocco, Namibia, South Africa, Tanzania
Europe
France, Greece, Romania, Scotland, Spain
Austria, Finland, Germany, Italy, Romania, Turkey, United Kingdom
Deposits in Western Continents
North America
USA
Mexico, USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New Zealand, South Australia, Western Australia
New South Wales, New Zealand, Western Australia