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
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
Origin
New Zealand
Germany
Discoverer
Unknown
Van Tooren
Etymology
From German which means hornstone
From Greek tephra, ashes from Indo-European base, to burn
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Granular, Platy
Aphanitic to Porphyritic
Color
Brown, Dark Greenish - Grey, Green, Reddish Brown
Black, Brown, Green, Grey, White
Durability
Durable
Durable
Appearance
Dull
Vesicular
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Decorative Aggregates, Flooring, 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
Other Architectural Uses
Curbing
Curbing
Construction Industry
for Road Aggregate, Roadstone
Landscaping
Antiquity Uses
Artifacts, Monuments
Artifacts, Sculpture
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork
Production of Lime, Soil Conditioner
Types
Biotite hornfels
Igneous rock
Features
Smooth to touch
Host Rock for Lead
Archaeological Significance
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.
Tephrite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Mineral Content
Andalusite
Alkali feldspar, Nepheline, Plagioclase, Pyroxene
Compound Content
Fe, Mg
CaO, Carbon Dioxide, MgO, Silicon Dioxide
Types of Metamorphism
-
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional 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, Sea Erosion, Water Erosion
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal
Uneven
Porosity
Highly Porous
Very Less Porous
Luster
Shiny
Subvitreous to Dull
Cleavage
Perfect
Crenulation and Pervasive
Specific Gravity
3.4-3.9
2.86
Transparency
Opaque
Opaque
Density
0.25-0.30 g/cm3
2.8-2.9 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
-
Africa
Cameroon, East Africa, Tanzania, Western Africa
Namibia, Uganda
Europe
United Kingdom
Germany, Hungary, Italy, Portugal, Spain
Deposits in Western Continents
North America
Canada, USA
USA
South America
Bolivia, Brazil, Colombia, Ecuador
-
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Western Australia
New Zealand, Western Australia
All about Hornfels and Tephrite Properties
Know all about Hornfels and Tephrite properties here. All properties of rocks are important as they define the type of rock and its application. Hornfels belongs to Metamorphic Rocks while Tephrite belongs to Igneous Rocks.Texture of Hornfels is Granular, Platy whereas that of Tephrite is Aphanitic to Porphyritic. Hornfels appears Dull and Tephrite appears Vesicular. The luster of Hornfels is shiny while that of Tephrite is subvitreous to dull. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas Tephrite is available in black, brown, green, grey, white colors. The commercial uses of Hornfels are cemetery markers, commemorative tablets, creating artwork and that of Tephrite are production of lime, soil conditioner.