Rhyolite and Coquina

Rhyolite

Coquina

Definition

Rhyolite is a fine-grained igneous rock which is rich in silica

Coquina is a sedimentary rock that is composed either wholly or almost entirely of the transported, abraded, and mechanically-sorted fragments of the shells of molluscs, trilobites, brachiopods, or other invertebrates

History

Origin

North America

European Foreland Basins

Discoverer

Ferdinand von Richthofen

Unknown

Etymology

From German Rhyolit, from Greek rhuax lava stream + lithos stone

From Concha (Latin)+ Coquina(Spanish) +conch(English)= Couquina (mid 19th century)

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Soft Rock

Family

Group

Volcanic

Not Applicable

Other Categories

Coarse Grained Rock, Opaque Rock

Texture

Aphanitic, Glassy, Porphyritic

Clastic

Color

Grey, White, Light Black

Beige, Buff, Orange

Maintenance

Durability

Durable

Non-Durable

Water Resistant

Yes

Scratch Resistant

Yes

Stain Resistant

Yes

Wind Resistant

Yes

Acid Resistant

Yes

Appearance

Banded

Layered, Banded, Veined and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens

Decorative Aggregates, Homes, Hotels, Interior Decoration

Exterior Uses

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

Garden Decoration, Office Buildings

Other Architectural Uses

Not Yet Used

Curbing

Industry

Construction Industry

Arrowheads, As Dimension Stone, Building houses or walls, Construction Aggregate, Cutting Tool, for Road Aggregate, Knives

Building houses or walls, Construction Aggregate

Medical Industry

Not Yet Used

Antiquity Uses

Artifacts

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Gemstone, Laboratory bench tops, Jewelry

Creating Artwork

Types

Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks.

Not Available

Features

Acidic in nature, Available in lots of colors

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

Archaeological Significance

Monuments

Not Yet Used

Used

Famous Monuments

Not Applicable

Data Not Available

Sculpture

Not Yet Used

Used

Famous Sculptures

Not Applicable

Data Not Available

Pictographs

Not Used

Used

Petroglyphs

Not Used

Used

Figurines

Not Yet Used

Used

Fossils

Absent

Present

Formation

Rhyolite is a felsic extrusive rock and due to its high silica content, rhyolite lava is very viscous and is volcanic equivalent of granite.

Coquina is a sedimentary rock which is formed when billions of small clam-like seashell, called Coquina, or cockleshell are die and hence are deposited, buried and turns into a rock when pressure is applied.

Composition

Mineral Content

Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz

Apatite, Augite, Bronzite, Calcite, Chert, Chlorite, Clay Minerals, Epidote, Feldspar, Garnet, Micas, Muscovite or Illite

Compound Content

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

CaO, Carbon Dioxide, Iron(III) Oxide, MgO

Transformation

Metamorphism

Yes

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Not Applicable

Weathering

Yes

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

Yes

Types of Erosion

Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion

Coastal Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

6-7

1-2

Grain Size

Large and Coarse Grained

Coarse Grained

Fracture

Sub-conchoidal

Irregular

Streak

Colorless

White

Porosity

Highly Porous

Luster

Earthy

Dull to Vitreous to Submetallic

Compressive Strength

140.00 N/mm²

Not Available

Cleavage

Not Available

Toughness

Not Available

Specific Gravity

2.65-2.67

1.10-2.24

Transparency

Opaque

Density

2.4-2.6 g/cm³

2.8-2.9 g/cm³

Thermal Properties

Resistance

Heat Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India

Not Yet Found

Africa

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

Not Yet Found

Europe

Germany, Iceland, Ireland, Italy, Spain

United Kingdom

Others

Not Yet Found

Deposits in Western Continents

North America

Canada, USA

USA

South America

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

Not Yet Found

Deposits in Oceania Continent

Australia

New Zealand, Queensland, Western Australia

Not Yet Found

Summary >>

<< Reserves

All about Rhyolite and Coquina Properties

Know all about Rhyolite and Coquina properties here. All properties of rocks are important as they define the type of rock and its application. Rhyolite belongs to Igneous Rocks while Coquina belongs to Sedimentary Rocks.Texture of Rhyolite is Aphanitic, Glassy, Porphyritic whereas that of Coquina is Clastic. Rhyolite appears Banded and Coquina appears Layered, Banded, Veined and Shiny. The luster of Rhyolite is earthy while that of Coquina is dull to vitreous to submetallic. Rhyolite is available in grey, white, light black colors whereas Coquina is available in beige, buff, orange colors. The commercial uses of Rhyolite are gemstone, laboratory bench tops, jewelry and that of Coquina are creating artwork.