Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
  
Boninite is a mafic extrusive rock which is high in magnesium and silica content, formed in fore-arc environments, typically during the early stages of subduction
  
History
  
  
Origin
Romania and Moldova, Europe
  
Japan
  
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 its occurrence in the Izu-Bonin arc south of Japan
  
Class
Igneous Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Soft Rock
  
Durable Rock, Hard Rock
  
Family
  
  
Group
Volcanic
  
Volcanic
  
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, Brown, Colourless, Green, Grey
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
No
  
No
  
Scratch Resistant
No
  
Yes
  
Stain Resistant
No
  
Yes
  
Wind Resistant
No
  
Yes
  
Acid Resistant
No
  
No
  
Appearance
Vesicular
  
Dull and Soft
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
  
Decorative Aggregates, Homes, Kitchens
  
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration
  
Garden Decoration, Office Buildings
  
Other Architectural Uses
Curbing
  
Not Yet Used
  
Industry
  
  
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
  
As a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement, Manufacture of Magnesium and Dolomite Refractories
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts
  
Artifacts
  
Other Uses
  
  
Commercial Uses
Commemorative Tablets, Creating Artwork
  
An Oil and Gas Reservoir, Cemetery Markers, Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
  
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, High Mg content, Is one of the oldest rock
  
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
  
Pictographs
Used
  
Not Used
  
Petroglyphs
Used
  
Not Used
  
Figurines
Not Yet Used
  
Not Yet Used
  
Fossils
Absent
  
Absent
  
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.
  
Boninite is a type of Igneous rock which is formed through the cooling and solidification of lava or existing rocks.
  
Composition
  
  
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
  
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Ilmenite
  
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
  
Silicon Dioxide
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
  
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Regional Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Biological Weathering
  
Erosion
Yes
  
Yes
  
Types of Erosion
Chemical Erosion
  
Chemical Erosion, Coastal Erosion, Wind Erosion
  
Physical Properties
  
  
Hardness
2-2.25
  
7
  
Grain Size
Medium to Fine Coarse Grained
  
Fine Grained
  
Fracture
Conchoidal
  
Uneven
  
Streak
White
  
White
  
Porosity
Less Porous
  
Less Porous
  
Luster
Subvitreous to Dull
  
Vitreous
  
Cleavage
Perfect
  
Not Available
  
Toughness
Not Available
  
1.1
  
Specific Gravity
2.86-2.87
  
2.5-2.8
  
Transparency
Translucent
  
Opaque
  
Density
2.77-2.771 g/cm3
  
Not Available
  
Thermal Properties
  
  
Specific Heat Capacity
0.92 kJ/Kg K
  
10
Not Available
  
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
  
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
  
Deposits in Eastern Continents
  
  
Asia
Not Yet Found
  
Not Available
  
Africa
Not Yet Found
  
South Africa
  
Europe
France, Greece, Romania, Scotland, Spain
  
England, Finland, United Kingdom
  
Others
Not Yet Found
  
Antarctica, Greenland
  
Deposits in Western Continents
  
  
North America
USA
  
USA
  
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
  
Colombia, Uruguay
  
Deposits in Oceania Continent
  
  
Australia
New Zealand, South Australia, Western Australia
  
New Zealand, Western Australia