Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Websterite is ultramafic and ultrabasic rock that consists of roughly equal proportions of orthopyroxene and clinopyroxene. It is a special type of pyroxenite.
Origin
Romania and Moldova, Europe
Webster, North Carolina
Discoverer
Unknown
Unknown
Etymology
From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described
From the town of Webster located in North Carolina
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Clastic, Granular, Phaneritic, Porphyritic
Color
Bluish - Grey, Brown, Grey, Light to Dark Grey
Black to Grey, Bluish - Grey, Dark Greenish - Grey, Green, Light Greenish Grey
Durability
Durable
Durable
Appearance
Vesicular
Layered, Banded, Veined and Shiny
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Interior Decoration
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
Commemorative Tablets, Creating Artwork
Cemetery Markers, Commemorative Tablets, Creating Artwork, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Types
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Ultramafic rock
Features
Host Rock for Lead, Is one of the oldest rock
Generally rough to touch, Is one of the oldest rock
Archaeological Significance
Formation
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.
Websterite can be formed as cumulates in ultramafic intrusions by accumulation of pyroxene crystals at the base of the lava chamber.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Amphibole, Augite, Bronzite, Chromite, Diopside, Enstatite, Garnet, Hornblende, Hypersthene, Magnetite, Pyroxene
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
Burial Metamorphism, Impact Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Grain Size
Medium to Fine Coarse Grained
Coarse Grained
Fracture
Conchoidal
Uneven
Streak
White
White, Greenish White or Grey
Porosity
Less Porous
Less Porous
Luster
Subvitreous to Dull
Dull to Vitreous to Submetallic
Specific Gravity
2.86-2.87
3.2-3.5
Transparency
Translucent
Opaque
Density
2.77-2.771 g/cm3
3.1-3.6 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Europe
France, Greece, Romania, Scotland, Spain
Germany, Greece, Italy, Scotland, Turkey
Deposits in Western Continents
North America
USA
Canada, USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Brazil, Colombia, Venezuela
Deposits in Oceania Continent
Australia
New Zealand, South Australia, Western Australia
New Zealand, Queensland
All about Dacite and Websterite Properties
Know all about Dacite and Websterite properties here. All properties of rocks are important as they define the type of rock and its application. Dacite and Websterite belong to Igneous Rocks.Texture of Dacite is Aphanitic to Porphyritic whereas that of Websterite is Clastic, Granular, Phaneritic, Porphyritic. Dacite appears Vesicular and Websterite appears Layered, Banded, Veined and Shiny. The luster of Dacite is subvitreous to dull while that of Websterite is dull to vitreous to submetallic. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas Websterite is available in black to grey, bluish - grey, dark greenish - grey, green, light greenish grey colors. The commercial uses of Dacite are commemorative tablets, creating artwork and that of Websterite are cemetery markers, commemorative tablets, creating artwork, laboratory bench tops, jewelry, sea defence, tombstones.