Dacite and Phyllite

Dacite

Phyllite

Definition

Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite

Phyllite is a fine-grained metamorphic rock with a well-developed laminar structure, and is intermediate between slate and schist rocks

History

Origin

Romania and Moldova, Europe

Unknown

Discoverer

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 Greek phullon leaf + -ite1

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Soft Rock

Family

Group

Volcanic

Not Applicable

Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Aphanitic to Porphyritic

Phyllitic Sheen, Slaty

Color

Bluish - Grey, Brown, Grey, Light to Dark Grey

Black to Grey, Light Greenish Grey

Maintenance

Less

Durability

Durable

Water Resistant

Scratch Resistant

Stain Resistant

Wind Resistant

Acid Resistant

Appearance

Vesicular

Crinkled or Wavy

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Decorative Aggregates, Floor Tiles, Homes, Interior Decoration

Exterior Uses

As Building Stone, Paving Stone, Garden Decoration

As Building Stone, As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

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, Raw material for the manufacture of mortar, Roadstone

Medical Industry

Not Yet Used

Antiquity Uses

Artifacts

Artifacts, Sculpture

Other Uses

Commercial Uses

Commemorative Tablets, Creating Artwork

Cemetery Markers, Commemorative Tablets, Creating Artwork, Writing Slates

Types

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Not Available

Features

Host Rock for Lead, Is one of the oldest rock

Easily splits into thin plates, Is one of the oldest rock, Surfaces are often shiny

Archaeological Significance

Monuments

Not Yet Used

Famous Monuments

Not Applicable

Sculpture

Not Yet Used

Used

Famous Sculptures

Not Applicable

Data Not Available

Pictographs

Used

Petroglyphs

Used

Figurines

Not Yet Used

Used

Fossils

Absent

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.

Phyllite is a metamorphic rock which is formed by regional metamorphism of argillaceous sediments since their cleavage arose due to deviatoric stress.

Composition

Mineral Content

Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon

Albite, Alusite, Amphibole, Apatite, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Sillimanite, Staurolite, Talc, Zircon

Compound Content

Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide

CaO, Carbon Dioxide, MgO

Transformation

Metamorphism

Yes

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Not Applicable

Weathering

Yes

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

Yes

Types of Erosion

Chemical Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

2-2.25

1-2

Grain Size

Medium to Fine Coarse Grained

Fracture

Conchoidal

Streak

White

Porosity

Less Porous

Highly Porous

Luster

Subvitreous to Dull

Phyllitic

Cleavage

Perfect

Crenulation and Pervasive

Toughness

Not Available

1.2

Specific Gravity

2.86-2.87

2.72-2.73

Transparency

Translucent

Opaque

Density

2.77-2.771 g/cm³

2.18-3.3 g/cm³

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K

Not Available

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Pressure Resistant, Water Resistant

Reserves

Deposits in Eastern Continents

Asia

Not Yet Found

Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam

Africa

Not Yet Found

Egypt, Ethiopia, Morocco, Nigeria, South Africa

Europe

France, Greece, Romania, Scotland, Spain

Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland

Others

Not Yet Found

Deposits in Western Continents

North America

USA

Canada, Costa Rica, Cuba, Mexico, Panama, USA

South America

Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Brazil, Colombia, Guyana

Deposits in Oceania Continent

Australia

New Zealand, South Australia, Western Australia

New South Wales, New Zealand, Queensland

Summary >>

<< Reserves

All about Dacite and Phyllite Properties

Know all about Dacite and Phyllite properties here. All properties of rocks are important as they define the type of rock and its application. Dacite belongs to Igneous Rocks while Phyllite belongs to Metamorphic Rocks.Texture of Dacite is Aphanitic to Porphyritic whereas that of Phyllite is Phyllitic Sheen, Slaty. Dacite appears Vesicular and Phyllite appears Crinkled or Wavy. The luster of Dacite is subvitreous to dull while that of Phyllite is phyllitic. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas Phyllite is available in black to grey, light greenish grey colors. The commercial uses of Dacite are commemorative tablets, creating artwork and that of Phyllite are cemetery markers, commemorative tablets, creating artwork, writing slates.