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
Rhyodacite is an extrusive volcanic rock intermediate in composition between dacite and rhyolite
Discoverer
Unknown
Unknown
Etymology
From German which means hornstone
Rhyo lite + dacite : a rock intermediate between rhyolite and dacite that is the extrusive equivalent of granodiorite
Class
Metamorphic Rocks
Igneous 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
Earthy
Color
Brown, Dark Greenish - Grey, Green, Reddish Brown
Black to Grey, Dark Greenish - Grey
Durability
Durable
Durable
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
for Road Aggregate, Roadstone
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
Antiquity Uses
Artifacts, Monuments
Artifacts
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork
Cemetery Markers, Creating Artwork
Types
Biotite hornfels
Intermediate volcanic rock
Features
Smooth to touch
Available in Lots of Colors and Patterns
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.
Rhyodacite 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
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Compound Content
Fe, Mg
Ca, Fe, Potassium Oxide, Potassium, Silicon Dioxide
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal 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
Grain Size
Fine Grained
Fine Grained
Fracture
Conchoidal
Conchoidal
Porosity
Highly Porous
Less Porous
Luster
Shiny
Greasy to Dull
Specific Gravity
3.4-3.9
2.34-2.40
Transparency
Opaque
Opaque
Density
0.25-0.30 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
Africa
Cameroon, East Africa, Tanzania, Western Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Europe
United Kingdom
Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Bolivia, Brazil, Colombia, Ecuador
-
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Western Australia
-
Hornfels vs Rhyodacite 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 Rhyodacite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Hornfels and Properties of Rhyodacite. Learn more about Hornfels vs Rhyodacite in the next section. The interior uses of Hornfels include Decorative aggregates, Flooring, Homes and Interior decoration whereas the interior uses of Rhyodacite include Decorative aggregates and Interior decoration. Due to some exceptional properties of Hornfels and Rhyodacite, they have various applications in construction industry. The uses of Hornfels in construction industry include For road aggregate, Roadstone and that of Rhyodacite include As dimension stone, Construction aggregate, For road aggregate, Landscaping.
More about Hornfels and Rhyodacite
Here you can know more about Hornfels and Rhyodacite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Hornfels and Rhyodacite consists of mineral content and compound content. The mineral content of Hornfels includes Andalusite and mineral content of Rhyodacite includes Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon. You can also check out the list of all Metamorphic Rocks. When we have to compare Hornfels vs Rhyodacite, 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, Rhyodacite is available in black to grey, dark greenish - grey colors. Appearance of Hornfels is Dull and that of Rhyodacite is Skeletal. Properties of rock is another aspect for Hornfels vs Rhyodacite. The hardness of Hornfels is 2-3 and that of Rhyodacite is 5.5-6. The types of Hornfels are Biotite hornfels whereas types of Rhyodacite are Intermediate volcanic rock. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Hornfels is while that of Rhyodacite is black. The specific heat capacity of Hornfels is 0.84 kJ/Kg K and that of Rhyodacite is 1.12 kJ/Kg K. 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 Rhyodacite is heat resistant.