Gossan

Dacite

Gossan and Dacite

Gossan

Dacite

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Definition

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

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

History

Origin

Indonesia

Romania and Moldova, Europe

Discoverer

Cornish Gossen

Unknown

Etymology

From Cornish gossen from gos, blood from Old Cornish guit

From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Soft Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Rough, Sandy

Aphanitic to Porphyritic

Color

Brown, Brown- Black, Gold, Green, Rust

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Banded

Vesicular

Uses

Architecture

Interior Uses

Countertops, Decorative Aggregates, Interior Decoration

Decorative Aggregates, Entryways, Interior Decoration

Exterior Uses

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

As Building Stone, Paving Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate

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

Medical Industry

Antiquity Uses

Artifacts

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Gemstone

Commemorative Tablets, Creating Artwork

Types

Translocated gossan and Leakage gossan

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Features

Clasts are smooth to touch, Easily splits into thin plates

Host Rock for Lead, Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

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

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

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

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

Compound Content

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

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

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, Sea Erosion, Wind Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

4-52-2.25

1 7

👆🏻

Grain Size

Fine to Medium Grained

Medium to Fine Coarse Grained

Fracture

Conchoidal

Streak

White to Grey

White

Porosity

Highly Porous

Less Porous

Luster

Metallic

Subvitreous to Dull

Compressive Strength

-70.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

Specific Gravity

2.02.86-2.87

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

-9999 g/cm³2.77-2.771 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.24 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Africa

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

Europe

Albania, France, Germany, Great Britain, United Kingdom

France, Greece, Romania, Scotland, Spain

Others

Deposits in Western Continents

North America

Canada, USA

USA

South America

Brazil, Colombia, Ecuador

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

Deposits in Oceania Continent

Australia

New South Wales, South Australia, Western Australia

New Zealand, South Australia, Western Australia

All about Gossan and Dacite Properties

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