Dacite

Gossan

Dacite and Gossan

Dacite

Gossan

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Definition

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

Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.

History

Origin

Romania and Moldova, Europe

Indonesia

Discoverer

Unknown

Cornish Gossen

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 Cornish gossen from gos, blood from Old Cornish guit

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Soft Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Aphanitic to Porphyritic

Rough, Sandy

Color

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

Brown, Brown- Black, Gold, Green, Rust

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Vesicular

Dull and Banded

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Countertops, Decorative Aggregates, 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

Medical Industry

Antiquity Uses

Artifacts

Other Uses

Commercial Uses

Commemorative Tablets, Creating Artwork

Cemetery Markers, Commemorative Tablets, Gemstone

Types

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Translocated gossan and Leakage gossan

Features

Host Rock for Lead, Is one of the oldest rock

Clasts are smooth to touch, Easily splits into thin plates

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.

Earth movements can cause rocks to be either deeply buried or squeezed and hence the rocks are heated and put under great pressure.

Composition

Mineral Content

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

Apatite, Augite, Biotite, Bronzite, Calcite, Chert, Epidote, Feldspar, Hornblende, Micas, Plagioclase, Pyroxene, Quartz, Sulfides, Zircon

Compound Content

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

Aluminium Oxide, CaO, Fe, FeO, Silicon Dioxide, Sulphur

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Chemical Erosion, Sea Erosion, Wind Erosion

Properties

Physical Properties

Hardness

2-2.254-5

1 7

👆🏻

Grain Size

Medium to Fine Coarse Grained

Fine to Medium Grained

Fracture

Conchoidal

Streak

White

White to Grey

Porosity

Less Porous

Highly Porous

Luster

Subvitreous to Dull

Metallic

Compressive Strength

70.00 N/mm²-

0.15 450

👆🏻

Cleavage

Perfect

Toughness

Specific Gravity

2.86-2.872.0

0 8.4

👆🏻

Transparency

Translucent

Opaque

Density

2.77-2.771 g/cm³-9999 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.24 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Indonesia, Russia, Singapore, South Korea

Africa

Cape Verde, Ethiopia, Ghana, South Africa, Western Africa

Europe

France, Greece, Romania, Scotland, Spain

Albania, France, Germany, Great Britain, United Kingdom

Others

Deposits in Western Continents

North America

USA

Canada, USA

South America

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

Brazil, Colombia, Ecuador

Deposits in Oceania Continent

Australia

New Zealand, South Australia, Western Australia

New South Wales, South Australia, Western Australia

All about Dacite and Gossan Properties

Know all about Dacite and Gossan properties here. All properties of rocks are important as they define the type of rock and its application. Dacite belongs to Igneous Rocks while Gossan belongs to Metamorphic Rocks.Texture of Dacite is Aphanitic to Porphyritic whereas that of Gossan is Rough, Sandy. Dacite appears Vesicular and Gossan appears Dull and Banded. The luster of Dacite is subvitreous to dull while that of Gossan is metallic. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas Gossan is available in brown, brown- black, gold, green, rust colors. The commercial uses of Dacite are commemorative tablets, creating artwork and that of Gossan are cemetery markers, commemorative tablets, gemstone.