Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
  
Variolites are a group of dark green basic igneous rocks which exhibit pale colored spots, or spherules, especially on weathered surfaces, that give them a pockmarked appearance
  
History
  
  
Origin
Romania and Moldova, Europe
  
France
  
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 Latin varius, speckled, variegated
  
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
  
Opaque Rock
  
Texture
Aphanitic to Porphyritic
  
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
  
Color
Bluish - Grey, Brown, Grey, Light to Dark Grey
  
Black, Brown, Light to Dark Grey
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
No
  
Yes
  
Scratch Resistant
No
  
Yes
  
Stain Resistant
No
  
No
  
Wind Resistant
No
  
No
  
Acid Resistant
No
  
Yes
  
Appearance
Vesicular
  
Dull and Soft
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
  
Floor Tiles, Flooring, Homes, Hotels, Kitchens
  
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration
  
Garden Decoration, Office Buildings
  
Other Architectural Uses
Curbing
  
Curbing
  
Industry
  
  
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
  
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts
  
Artifacts, Monuments, Sculpture
  
Other Uses
  
  
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
  
Has High structural resistance against erosion and climate, Very fine grained rock
  
Archaeological Significance
  
  
Monuments
Not Yet Used
  
Used
  
Famous Monuments
Not Applicable
  
Data Not Available
  
Sculpture
Not Yet Used
  
Used
  
Famous Sculptures
Not Applicable
  
Data Not Available
  
Pictographs
Used
  
Used
  
Petroglyphs
Used
  
Used
  
Figurines
Not Yet Used
  
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.
  
Variolites are a group of dark green basic igneous rocks that exhibit pale colored spots on weathered surfaces that give them a pockmarked appearance.
  
Composition
  
  
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
  
Olivine, Plagioclase, Pyroxene
  
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
  
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
  
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
Yes
  
No
  
Types of Erosion
Chemical Erosion
  
Not Applicable
  
Physical Properties
  
  
Hardness
2-2.25
  
6
  
Grain Size
Medium to Fine Coarse Grained
  
Not Applicable
  
Fracture
Conchoidal
  
Conchoidal
  
Streak
White
  
White to Grey
  
Porosity
Less Porous
  
Less Porous
  
Luster
Subvitreous to Dull
  
Not Available
  
Compressive Strength
Not Available
  
37.50 N/mm
2
  
27
Cleavage
Perfect
  
Not Available
  
Toughness
Not Available
  
2.3
  
Specific Gravity
2.86-2.87
  
2.8-3
  
Transparency
Translucent
  
Opaque
  
Density
2.77-2.771 g/cm3
  
2.9-3.1 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
0.92 kJ/Kg K
  
10
0.84 kJ/Kg K
  
15
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
  
Heat Resistant, Pressure Resistant, Wear Resistant
  
Deposits in Eastern Continents
  
  
Asia
Not Yet Found
  
India, Russia
  
Africa
Not Yet Found
  
South Africa
  
Europe
France, Greece, Romania, Scotland, Spain
  
Iceland
  
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
  
Brazil
  
Deposits in Oceania Continent
  
  
Australia
New Zealand, South Australia, Western Australia
  
Not Yet Found
  
Dacite vs Variolite Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Dacite vs Variolite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Dacite and Properties of Variolite. Learn more about Dacite vs Variolite in the next section. The interior uses of Dacite include Decorative aggregates, Entryways and Interior decoration whereas the interior uses of Variolite include Floor tiles, Flooring, Homes, Hotels and Kitchens. Due to some exceptional properties of Dacite and Variolite, they have various applications in construction industry. The uses of Dacite in construction industry include As dimension stone, Construction aggregate, For road aggregate, Landscaping and that of Variolite include As dimension stone, Cobblestones, Rail track ballast, Roadstone.
More about Dacite and Variolite
Here you can know more about Dacite and Variolite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Dacite and Variolite consists of mineral content and compound content. The mineral content of Dacite includes Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon and mineral content of Variolite includes Olivine, Plagioclase, Pyroxene. You can also check out the list of all Igneous Rocks. When we have to compare Dacite vs Variolite, the texture, color and appearance plays an important role in determining the type of rock. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas, Variolite is available in black, brown, light to dark grey colors. Appearance of Dacite is Vesicular and that of Variolite is Dull and Soft. Properties of rock is another aspect for Dacite vs Variolite. The hardness of Dacite is 2-2.25 and that of Variolite is 6. The types of Dacite are Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite whereas types of Variolite are Not Available. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Dacite is white while that of Variolite is white to grey. The specific heat capacity of Dacite is 0.92 kJ/Kg K and that of Variolite is 0.84 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Dacite is heat resistant, impact resistant, pressure resistant, wear resistant whereas Variolite is heat resistant, pressure resistant, wear resistant.