Definition
It is a metamorphic magnesium rich rock because it is composed of the mineral talc
  
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
  
History
  
  
Origin
USA
  
Romania and Moldova, Europe
  
Discoverer
Unknown
  
Unknown
  
Etymology
From 17th century, because of its greasy feel and use like a soap
  
From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described
  
Class
Metamorphic Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Soft Rock
  
Durable Rock, Soft Rock
  
Family
  
  
Group
Not Applicable
  
Volcanic
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Fine Grained Rock, Medium Grained Rock, Opaque Rock
  
Texture
Polished
  
Aphanitic to Porphyritic
  
Color
Black, Black to Grey, Green, Grey
  
Bluish - Grey, Brown, Grey, Light to Dark Grey
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
No
  
Scratch Resistant
No
  
No
  
Stain Resistant
No
  
No
  
Wind Resistant
No
  
No
  
Acid Resistant
No
  
No
  
Appearance
Dull, Banded and Foilated
  
Vesicular
  
Architecture
  
  
Interior Uses
Bathrooms, Decorative Aggregates, Homes, Interior Decoration
  
Decorative Aggregates, Entryways, Interior Decoration
  
Exterior Uses
As Facing Stone, Garden Decoration
  
As Building Stone, Paving Stone, Garden Decoration
  
Other Architectural Uses
Curbing
  
Curbing
  
Industry
  
  
Construction Industry
Manufacture of Magnesium and Dolomite Refractories
  
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
  
Medical Industry
Taken as a Supplement for Calcium or Magnesium
  
Not Yet Used
  
Antiquity Uses
Artifacts, Jewellery, Monuments, Sculpture
  
Artifacts
  
Other Uses
  
  
Commercial Uses
Cemetery Markers, Creating Artwork, Gemstone, Jewelry, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Production of Lime, Source of Magnesia (MgO)
  
Commemorative Tablets, Creating Artwork
  
Types
Not Available
  
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
  
Features
Host Rock for Lead
  
Host Rock for Lead, Is one of the oldest rock
  
Archaeological Significance
  
  
Monuments
Used
  
Not Yet Used
  
Famous Monuments
Christ the Redeemer in Rio de Janeiro, Stonehenge in English county of Wiltshire
  
Not Applicable
  
Sculpture
Used
  
Not Yet Used
  
Famous Sculptures
Data Not Available
  
Not Applicable
  
Pictographs
Used
  
Used
  
Petroglyphs
Used
  
Used
  
Figurines
Used
  
Not Yet Used
  
Fossils
Absent
  
Absent
  
Formation
Soapstone is a talc-schist, which is a type of metamorphic rock and it is largely composed of the mineral talc and is thus rich inmagnesium.
  
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.
  
Composition
  
  
Mineral Content
Albite, Apatite, Biotite, Calcite, Carbonate, Clay Minerals, Hornblende, Ilmenite, Micas, Plagioclase, Pyroxene, Quartz
  
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
  
Compound Content
CaO, Mg, MgO
  
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Burial Metamorphism, Cataclastic Metamorphism
  
Weathering
No
  
Yes
  
Types of Weathering
Not Applicable
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
No
  
Yes
  
Types of Erosion
Not Applicable
  
Chemical Erosion
  
Physical Properties
  
  
Hardness
1
  
2-2.25
  
Grain Size
Fine Grained
  
Medium to Fine Coarse Grained
  
Fracture
Conchoidal
  
Conchoidal
  
Streak
Black
  
White
  
Porosity
Less Porous
  
Less Porous
  
Luster
Greasy
  
Subvitreous to Dull
  
Compressive Strength
225.00 N/mm
2
  
7
Not Available
  
Cleavage
Perfect
  
Perfect
  
Toughness
1
  
Not Available
  
Specific Gravity
2.86
  
2.86-2.87
  
Transparency
Opaque
  
Translucent
  
Density
2.8-2.9 g/cm3
  
2.77-2.771 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
0.88 kJ/Kg K
  
13
0.92 kJ/Kg K
  
10
Resistance
Heat Resistant, Pressure Resistant
  
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
  
Deposits in Eastern Continents
  
  
Asia
China, India, Indonesia, Japan, North Korea, Russia, Saudi Arabia, Singapore, South Korea, Sri Lanka, Tajikistan, Thailand
  
Not Yet Found
  
Africa
Egypt, Ethiopia, Ghana, South Africa, Western Africa
  
Not Yet Found
  
Europe
Austria, England, Finland, France, Germany, Greece, Spain, Sweden, Switzerland, United Kingdom
  
France, Greece, Romania, Scotland, Spain
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
USA
  
South America
Colombia
  
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
  
Deposits in Oceania Continent
  
  
Australia
Central Australia, New Zealand, Queensland
  
New Zealand, South Australia, Western Australia