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
Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles
Discoverer
Unknown
Johann Gottlob Lehmann
Etymology
From German which means hornstone
From German Schalstein laminated limestone, and Schalgebirge layer of stone in stratified rock. From Old English scealu in its base sense of- thing that divides or separate,
Class
Metamorphic Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Granular, Platy
Clastic, Splintery
Color
Brown, Dark Greenish - Grey, Green, Reddish Brown
Black, Brown, Buff, Green, Grey, Red, Yellow
Durability
Durable
Durable
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, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
for Road Aggregate, Roadstone
Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
Antiquity Uses
Artifacts, Monuments
Artifacts, Sculpture
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork
Creating Artwork, Pottery
Types
Biotite hornfels
Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale
Features
Smooth to touch
Easily splits into thin plates, Generally rough to touch, Very fine grained rock
Archaeological Significance
Famous Monuments
-
Jantar Mantar in India
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.
Shale forms when very fine-grained clay particles are deposited in water which settle at the bottom of water bodies. They are later compacted hence forming shale.
Mineral Content
Andalusite
Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides
Compound Content
Fe, Mg
Ca, Fe, Mg, Silicon Dioxide, Sodium
Types of Metamorphism
-
-
Types of Weathering
Biological Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Fine Grained
Very fine-grained
Porosity
Highly Porous
Highly Porous
Specific Gravity
3.4-3.9
2.2-2.8
Transparency
Opaque
Opaque
Density
0.25-0.30 g/cm3
2.4-2.8 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand
Bangladesh, China, India, Russia
Africa
Cameroon, East Africa, Tanzania, Western Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Europe
United Kingdom
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Deposits in Western Continents
North America
Canada, USA
USA
South America
Bolivia, Brazil, Colombia, Ecuador
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Western Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia
All about Hornfels and Shale Properties
Know all about Hornfels and Shale properties here. All properties of rocks are important as they define the type of rock and its application. Hornfels belongs to Metamorphic Rocks while Shale belongs to Sedimentary Rocks.Texture of Hornfels is Granular, Platy whereas that of Shale is Clastic, Splintery. Hornfels appears Dull and Shale appears Muddy. The luster of Hornfels is shiny while that of Shale is dull. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas Shale is available in black, brown, buff, green, grey, red, yellow colors. The commercial uses of Hornfels are cemetery markers, commemorative tablets, creating artwork and that of Shale are creating artwork, pottery.