Dacite

Syenite

Dacite and Syenite

Dacite

Syenite

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Definition

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

Syenite is a coarse-grained igneous rock which is composed mainly of alkali feldspar and various ferromagnesian minerals

History

Origin

Romania and Moldova, Europe

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 French syénite, from Latin Syenites (lapis ) (stone) of Syene

Class

Igneous Rocks

Sub-Class

Durable Rock, Soft Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Plutonic

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

Earthy

Color

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

Brown, Buff, Cream, Green, Grey, Pink, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Vesicular

Banded and Foilated

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Flooring, Homes, Hotels, Interior Decoration

Exterior Uses

As Building Stone, Paving Stone, Garden Decoration

As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping

As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Manufacture of Magnesium and Dolomite Refractories

Medical Industry

Antiquity Uses

Artifacts

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Commemorative Tablets, Creating Artwork

Cemetery Markers, Creating Artwork

Types

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Shonkinite

Features

Host Rock for Lead, Is one of the oldest rock

Available in Lots of Colors and Patterns, Is one of the oldest rock, Matrix variable

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

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.

Syenites are formed due to alkaline igneous activities and are generally formed in thick continental crustal areas or in Cordilleran subduction zones.

Composition

Mineral Content

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

Amphibole, Biotite, Feldspar, Hornblade, Micas, Muscovite or Illite, Plagioclase, Pyroxene, Quartz

Compound Content

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

Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

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

Properties

Physical Properties

Hardness

2-2.255.5-6

1 7

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Grain Size

Medium to Fine Coarse Grained

Fracture

Conchoidal

Streak

White

Porosity

Less Porous

Luster

Subvitreous to Dull

Compressive Strength

70.00 N/mm²150.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

Specific Gravity

2.86-2.872.6-2.7

0 8.4

👆🏻

Transparency

Translucent

Opaque

Density

2.77-2.771 g/cm³2.6-2.8 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam

Africa

Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa

Europe

France, Greece, Romania, Scotland, Spain

Bulgaria, England, Germany, Norway, Romania, Switzerland

Others

Deposits in Western Continents

North America

USA

South America

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

Brazil, Chile

Deposits in Oceania Continent

Australia

New Zealand, South Australia, Western Australia

New Zealand, Queensland, South Australia, Western Australia

All about Dacite and Syenite Properties

Know all about Dacite and Syenite properties here. All properties of rocks are important as they define the type of rock and its application. Dacite and Syenite belong to Igneous Rocks.Texture of Dacite is Aphanitic to Porphyritic whereas that of Syenite is Earthy. Dacite appears Vesicular and Syenite appears Banded and Foilated. The luster of Dacite and Syenite is subvitreous to dull. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas Syenite is available in brown, buff, cream, green, grey, pink, white colors. The commercial uses of Dacite are commemorative tablets, creating artwork and that of Syenite are cemetery markers, creating artwork.