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
  
Essexite which is also known as nepheline monzogabbro, is a dark gray or black holocrystalline plutonic Iigneous Rock
  
History
  
  
Origin
New Zealand
  
USA
  
Discoverer
Unknown
  
Unknown
  
Etymology
From German which means hornstone
  
From the locality in Essex County, Massachusetts,US
  
Class
Metamorphic Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Soft Rock
  
Durable Rock, Hard Rock
  
Family
  
  
Group
Not Applicable
  
Plutonic
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Granular, Platy
  
Granular
  
Color
Brown, Dark Greenish - Grey, Green, Reddish Brown
  
Dark Grey to Black
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
Yes
  
Scratch Resistant
No
  
Yes
  
Stain Resistant
No
  
Yes
  
Wind Resistant
No
  
Yes
  
Acid Resistant
No
  
No
  
Appearance
Dull
  
Banded
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
  
Decorative Aggregates, Homes, Interior Decoration
  
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
  
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
  
Other Architectural Uses
Curbing
  
Curbing
  
Industry
  
  
Construction Industry
for Road Aggregate, Roadstone
  
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Monuments
  
Artifacts, Monuments, Sculpture, Small Figurines
  
Other Uses
  
  
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork
  
Cemetery Markers, Commemorative Tablets, Jewelry, Sea Defence, Tombstones
  
Types
Biotite hornfels
  
Not Available
  
Features
Smooth to touch
  
Is one of the oldest rock, Smooth to touch
  
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
  
Not Used
  
Petroglyphs
Used
  
Not 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.
  
Essexite is a type of igneous rock, which is usually dark grey to black plutonic rock. For the formation of essexite, suitable magma with exact composition of K, Ba, Rb, Cs, Sr should be produced.
  
Composition
  
  
Mineral Content
Andalusite
  
Augite, Feldspar, Hornblende, Nepheline, Olivine, Plagioclase, Pyroxene
  
Compound Content
Fe, Mg
  
Aluminium Oxide, Ba, Ca, Cs, Potassium, Rb, Sodium, Sr
  
Transformation
  
  
Metamorphism
No
  
Yes
  
Types of Metamorphism
Not Applicable
  
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering
  
Biological Weathering, Chemical Weathering
  
Erosion
Yes
  
Yes
  
Types of Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
  
Coastal Erosion, Glacier Erosion, Water Erosion
  
Physical Properties
  
  
Hardness
2-3
  
7
  
Grain Size
Fine Grained
  
Fine Grained
  
Fracture
Conchoidal
  
Conchoidal
  
Streak
Unknown
  
Black
  
Porosity
Highly Porous
  
Highly Porous
  
Luster
Shiny
  
Not Available
  
Compressive Strength
Not Available
  
Cleavage
Perfect
  
Not Available
  
Toughness
Not Yet Found
  
1.6
  
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
  
Impact 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
  
South Africa
  
Europe
United Kingdom
  
Germany, Greece, Italy, Scotland, Turkey
  
Others
Not Yet Found
  
Greenland
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
Canada, USA
  
South America
Bolivia, Brazil, Colombia, Ecuador
  
Brazil, Colombia, Venezuela
  
Deposits in Oceania Continent
  
  
Australia
New South Wales, New Zealand, Queensland, Western Australia
  
New Zealand, Queensland
  
Hornfels vs Essexite 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 Essexite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Hornfels and Properties of Essexite . Learn more about Hornfels vs Essexite in the next section. The interior uses of Hornfels include Decorative aggregates, Flooring, Homes and Interior decoration whereas the interior uses of Essexite include Decorative aggregates, Homes and Interior decoration. Due to some exceptional properties of Hornfels and Essexite , they have various applications in construction industry. The uses of Hornfels in construction industry include For road aggregate, Roadstone and that of Essexite include As dimension stone, Building houses or walls, Cement manufacture, Construction aggregate, For road aggregate.
More about Hornfels and Essexite
Here you can know more about Hornfels and Essexite . The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Hornfels and Essexite consists of mineral content and compound content. The mineral content of Hornfels includes Andalusite and mineral content of Essexite includes Augite, Feldspar, Hornblende, Nepheline, Olivine, Plagioclase, Pyroxene. You can also check out the list of all Metamorphic Rocks. When we have to compare Hornfels vs Essexite , 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, Essexite is available in dark grey to black colors. Appearance of Hornfels is Dull and that of Essexite is Banded. Properties of rock is another aspect for Hornfels vs Essexite . The hardness of Hornfels is 2-3 and that of Essexite is 7. The types of Hornfels are Biotite hornfels whereas types of Essexite 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 Essexite is black. The specific heat capacity of Hornfels is 0.84 kJ/Kg K and that of Essexite 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 Essexite is impact resistant, pressure resistant, wear resistant.