Definition
Hornfels is a metamorphic rock formed by the contact between mudstone or other clay rich rock, and a hot igneous body, and represents a heat altered equivalent of the original rock
  
Adakite is an intermediate to felsic volcanic rock that has geochemical characteristics of magma which is said to be formed by partial melting of altered basalt that is subducted below volcanic arcs
  
History
  
  
Origin
New Zealand
  
Adak, Aleutian Islands
  
Discoverer
Unknown
  
Defant and Drummond
  
Etymology
From German which means hornstone
  
From Adak, Aleutian Islands
  
Class
Metamorphic Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Soft Rock
  
Durable Rock, Medium Hardness Rock
  
Family
  
  
Group
Not Applicable
  
Volcanic
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Fine Grained Rock, Medium Grained Rock, Opaque Rock
  
Texture
Granular, Platy
  
Porphyritic
  
Color
Brown, Dark Greenish - Grey, Green, Reddish Brown
  
Black, Brown, 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
  
Yes
  
Acid Resistant
No
  
Yes
  
Appearance
Dull
  
Dull and Soft
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
  
Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens
  
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
  
As Building Stone, As Facing Stone, Office Buildings
  
Other Architectural Uses
Curbing
  
Whetstones
  
Industry
  
  
Construction Industry
for Road Aggregate, Roadstone
  
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Monuments
  
Monuments, Sculpture, Small Figurines
  
Other Uses
  
  
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork
  
Commemorative Tablets, Pottery, Used in aquariums
  
Types
Biotite hornfels
  
Not Available
  
Features
Smooth to touch
  
Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock
  
Archaeological Significance
  
  
Monuments
Used
  
Used
  
Famous Monuments
Data Not Available
  
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
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Hornfels is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
  
Adakite rocks are formed when the hydrous fluids are released from minerals that break down in metamorphosed basalt, and rise into the mantle they initiate partial melting.
  
Composition
  
  
Mineral Content
Andalusite
  
Olivine, Plagioclase, Pyroxene
  
Compound Content
Fe, Mg
  
Aluminium Oxide, MgO, Silicon Dioxide
  
Transformation
  
  
Metamorphism
No
  
Yes
  
Types of Metamorphism
Not Applicable
  
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering
  
Chemical Weathering, Mechanical Weathering
  
Erosion
Yes
  
Yes
  
Types of Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
  
Coastal Erosion, Sea Erosion, Water Erosion
  
Physical Properties
  
  
Hardness
2-3
  
3-4
  
Grain Size
Fine Grained
  
Fine to Medium Grained
  
Fracture
Conchoidal
  
Conchoidal
  
Streak
Unknown
  
Bluish Black
  
Porosity
Highly Porous
  
Less Porous
  
Luster
Shiny
  
Grainy, Pearly and Vitreous
  
Compressive Strength
Not Available
  
Cleavage
Perfect
  
Not Available
  
Toughness
Not Yet Found
  
Not Available
  
Specific Gravity
3.4-3.9
  
Not Available
  
Transparency
Opaque
  
Opaque
  
Density
0.25-0.30 g/cm3
  
Not Available
  
Thermal Properties
  
  
Specific Heat Capacity
0.84 kJ/Kg K
  
15
Not Available
  
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
  
Heat Resistant, Pressure Resistant, Wear Resistant
  
Deposits in Eastern Continents
  
  
Asia
Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand
  
India, Russia
  
Africa
Cameroon, East Africa, Tanzania, Western Africa
  
Ethiopia, Somalia, South Africa
  
Europe
United Kingdom
  
Iceland
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
Canada, USA
  
South America
Bolivia, Brazil, Colombia, Ecuador
  
Brazil
  
Deposits in Oceania Continent
  
  
Australia
New South Wales, New Zealand, Queensland, Western Australia
  
Not Yet Found
  
Hornfels vs Adakite 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. Hornfels vs Adakite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Hornfels and Properties of Adakite. Learn more about Hornfels vs Adakite in the next section. The interior uses of Hornfels include Decorative aggregates, Flooring, Homes and Interior decoration whereas the interior uses of Adakite include Decorative aggregates, Floor tiles, Homes, Hotels and Kitchens. Due to some exceptional properties of Hornfels and Adakite, they have various applications in construction industry. The uses of Hornfels in construction industry include For road aggregate, Roadstone and that of Adakite include As dimension stone, Cobblestones, Rail track ballast, Roadstone.
More about Hornfels and Adakite
Here you can know more about Hornfels and Adakite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Hornfels and Adakite consists of mineral content and compound content. The mineral content of Hornfels includes Andalusite and mineral content of Adakite includes Olivine, Plagioclase, Pyroxene. You can also check out the list of all Metamorphic Rocks. When we have to compare Hornfels vs Adakite, the texture, color and appearance plays an important role in determining the type of rock. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas, Adakite is available in black, brown, light to dark grey colors. Appearance of Hornfels is Dull and that of Adakite is Dull and Soft. Properties of rock is another aspect for Hornfels vs Adakite. The hardness of Hornfels is 2-3 and that of Adakite is 3-4. The types of Hornfels are Biotite hornfels whereas types of Adakite are Not Available. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Hornfels is unknown while that of Adakite is bluish black. The specific heat capacity of Hornfels is 0.84 kJ/Kg K and that of Adakite is Not Available. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Hornfels is heat resistant, impact resistant, pressure resistant whereas Adakite is heat resistant, pressure resistant, wear resistant.