Felsite and Dacite
Definition
Definition
Felsite is a very fine grained volcanic rock that may or may not contain larger crystals and light colored rock that typically requires petrographic examination or chemical analysis for more precise definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
History
Origin
Unknown
Romania and Moldova, Europe
Discoverer
Unknown
Unknown
Etymology
From English feldspar and -ite
From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Family
Group
Volcanic
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Texture
Arborescent Patterned, Vitreous
Aphanitic to Porphyritic
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Bluish - Grey, Brown, Grey, Light to Dark Grey
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
Yes
No
Scratch Resistant
Yes
No
Stain Resistant
No
No
Wind Resistant
Yes
No
Acid Resistant
No
No
Appearance
Layered, Banded, Veined and Shiny
Vesicular
Uses
Architecture
Interior Uses
Decorative Aggregates, Flooring, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
Paving Stone, Garden Decoration
As Building Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
Medical Industry
Surgery
Not Yet Used
Antiquity Uses
Artifacts
Artifacts
Other Uses
Commercial Uses
Mirror, Jewelry
Commemorative Tablets, Creating Artwork
Types
Types
Not Available
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Features
Available in Lots of Colors and Patterns, Clasts are smooth to touch, Splintery, Very fine grained rock
Host Rock for Lead, Is one of the oldest rock
Archaeological Significance
Monuments
Not Yet Used
Not Yet Used
Famous Monuments
Not Applicable
Not Applicable
Sculpture
Not Yet Used
Not Yet Used
Famous Sculptures
Not Applicable
Not Applicable
Pictographs
Used
Used
Petroglyphs
Used
Used
Figurines
Not Yet Used
Not Yet Used
Fossils
Absent
Absent
Formation
Formation
Felsite 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.
Dacitic magma is formed by the subduction of young oceanic crust under a thick felsic continental plate. Further, the Oceanic crust is hydrothermally altered as quartz and sodium are added.
Composition
Mineral Content
Feldspar, Iron Oxides
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Transformation
Metamorphism
Yes
Yes
Types of Metamorphism
Burial Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
Weathering
Yes
Yes
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
Yes
Yes
Types of Erosion
Chemical Erosion, Glacier Erosion, Water Erosion
Chemical Erosion
Properties
Physical Properties
Hardness
5-5.5
2-2.25
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal
Conchoidal
Streak
White
White
Porosity
Very Less Porous
Less Porous
Luster
Vitreous
Subvitreous to Dull
Compressive Strength
0.15 N/mm2
33
Not Available
Cleavage
Non-Existent
Perfect
Toughness
Not Available
Not Available
Specific Gravity
2.6-2.7
2.86-2.87
Transparency
Translucent
Translucent
Density
2.6 g/cm3
2.77-2.771 g/cm3
Thermal Properties
Specific Heat Capacity
0.92 kJ/Kg K
10
0.92 kJ/Kg K
10
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Reserves
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
Not Yet Found
Africa
Kenya
Not Yet Found
Europe
Greece, Hungary, Iceland, Italy, Turkey
France, Greece, Romania, Scotland, Spain
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, Mexico, USA
USA
South America
Argentina, Chile, Ecuador, Peru
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New Zealand
New Zealand, South Australia, Western Australia
All about Felsite and Dacite Properties
Know all about Felsite and Dacite properties here. All properties of rocks are important as they define the type of rock and its application. Felsite and Dacite belong to Igneous Rocks.Texture of Felsite is Arborescent Patterned, Vitreous whereas that of Dacite is Aphanitic to Porphyritic. Felsite appears Layered, Banded, Veined and Shiny and Dacite appears Vesicular. The luster of Felsite is vitreous while that of Dacite is subvitreous to dull. Felsite is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Dacite is available in bluish - grey, brown, grey, light to dark grey colors. The commercial uses of Felsite are mirror, jewelry and that of Dacite are commemorative tablets, creating artwork.
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