Definition
Rhyodacite is an extrusive volcanic rock intermediate in composition between dacite and rhyolite
Trondhjemite is a leucocratic (light-colored) intrusive igneous rock. It is a variety of tonalite in which the plagioclase is mostly in the form of oligoclase. Trondhjemites are sometimes known as plagiogranites.
Discoverer
Unknown
Unknown
Etymology
Rhyo lite + dacite : a rock intermediate between rhyolite and dacite that is the extrusive equivalent of granodiorite
From Trondheim, Norway
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Earthy
Phaneritic
Color
Black to Grey, Dark Greenish - Grey
Black, Brown, Light to Dark Grey, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Skeletal
Banded and Foilated
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration
Exterior Uses
As Building Stone, Garden Decoration
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
As Dimension Stone, Cement Manufacture, Cobblestones, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Cemetery Markers, Creating Artwork
Cemetery Markers, Creating Artwork
Types
Intermediate volcanic rock
Intermediate intrusive rock
Features
Available in Lots of Colors and Patterns
Is one of the oldest rock, Typically speckled black and white.
Archaeological Significance
Formation
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.
When alkali feldspar is extracted from granite, it changes to granitoid and later, it becomes trondhjemite with quartz as major mineral.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Albite, Amphibole, Apatite, Biotite, Feldspar, Hornblade, Ilmenite, Magnetite, Manganese Oxides, Olivine, Plagioclase, Pyroxene, Quartz, Sulfides, Titanite, Zircon
Compound Content
Ca, Fe, Potassium Oxide, Potassium, Silicon Dioxide
NaCl, CaO, MgO, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal
Conchoidal
Streak
Black
Bluish Black
Porosity
Less Porous
Very Less Porous
Luster
Greasy to Dull
Subvitreous to Dull
Specific Gravity
2.34-2.40
2.86-3
Transparency
Opaque
Opaque
Density
-9999 g/cm3
2.73 g/cm3
Resistance
Heat Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
-
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Egypt
Europe
Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland
Finland, Germany, Italy, Romania, Sweden, Turkey
Deposits in Western Continents
North America
Canada, USA
USA
South America
-
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru
Deposits in Oceania Continent
Australia
-
New Zealand, South Australia, Western Australia
Rhyodacite vs Trondhjemite 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. Rhyodacite vs Trondhjemite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Rhyodacite and Properties of Trondhjemite. Learn more about Rhyodacite vs Trondhjemite in the next section. The interior uses of Rhyodacite include Decorative aggregates and Interior decoration whereas the interior uses of Trondhjemite include Decorative aggregates, Entryways, Flooring, Homes and Interior decoration. Due to some exceptional properties of Rhyodacite and Trondhjemite, they have various applications in construction industry. The uses of Rhyodacite in construction industry include As dimension stone, Construction aggregate, For road aggregate, Landscaping and that of Trondhjemite include As dimension stone, Cement manufacture, Cobblestones, Construction aggregate, For road aggregate.
More about Rhyodacite and Trondhjemite
Here you can know more about Rhyodacite and Trondhjemite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Rhyodacite and Trondhjemite consists of mineral content and compound content. The mineral content of Rhyodacite includes Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon and mineral content of Trondhjemite includes Albite, Amphibole, Apatite, Biotite, Feldspar, Hornblade, Ilmenite, Magnetite, Manganese Oxides, Olivine, Plagioclase, Pyroxene, Quartz, Sulfides, Titanite, Zircon. You can also check out the list of all Igneous Rocks. When we have to compare Rhyodacite vs Trondhjemite, the texture, color and appearance plays an important role in determining the type of rock. Rhyodacite is available in black to grey, dark greenish - grey colors whereas, Trondhjemite is available in black, brown, light to dark grey, white colors. Appearance of Rhyodacite is Skeletal and that of Trondhjemite is Banded and Foilated. Properties of rock is another aspect for Rhyodacite vs Trondhjemite. The hardness of Rhyodacite is 5.5-6 and that of Trondhjemite is 6-7. The types of Rhyodacite are Intermediate volcanic rock whereas types of Trondhjemite are Intermediate intrusive rock. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Rhyodacite is black while that of Trondhjemite is bluish black. The specific heat capacity of Rhyodacite is 1.12 kJ/Kg K and that of Trondhjemite is 0.92 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Rhyodacite is heat resistant whereas Trondhjemite is heat resistant, pressure resistant, wear resistant.