Rhyolite

Picrite

Rhyolite and Picrite

Rhyolite

Picrite

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Definition

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

Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine

History

Origin

North America

Hawaii Islands

Discoverer

Ferdinand von Richthofen

Unknown

Etymology

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

From Greek pikros bitter + -ite, 19th century

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Coarse Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Aphanitic, Glassy, Porphyritic

Earthy, Rough

Color

Grey, White, Light Black

Black, Brown, Green, Grey, Pink, White, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Banded

Rough and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens

Countertops, Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

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

As a Sintering Agent in Steel Industry to process Iron Ore, Cement Manufacture, for Road Aggregate, Manufacture of Magnesium and Dolomite Refractories, Roadstone, Used for flooring, stair treads, borders and window sills.

Medical Industry

Antiquity Uses

Artifacts

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Gemstone, Laboratory bench tops, Jewelry

As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)

Types

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

Oceanite

Features

Acidic in nature, Available in lots of colors

Host Rock for Lead

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

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.

Picrite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

Composition

Mineral Content

Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz

Biotite, Olivine, Plagioclase, Pyrrhotite

Compound Content

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

Al, CaO, Carbon Dioxide, Mg, MgO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion

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

Properties

Physical Properties

Hardness

6-76.8

1 7

👆🏻

Grain Size

Large and Coarse Grained

Fine Grained

Fracture

Sub-conchoidal

Uneven

Streak

White, Greenish White or Grey

Porosity

Highly Porous

Less Porous

Luster

Earthy

Subvitreous to Dull

Compressive Strength

140.00 N/mm²189.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.1

Specific Gravity

2.65-2.672.75-2.92

0 8.4

👆🏻

Transparency

Opaque

Density

2.4-2.6 g/cm³1.5-2.5 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.71 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Wear Resistant

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India

India, Russia

Africa

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

South Africa

Europe

Germany, Iceland, Ireland, Italy, Spain

Iceland

Others

Deposits in Western Continents

North America

Canada, USA

South America

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

Brazil

Deposits in Oceania Continent

Australia

New Zealand, Queensland, Western Australia

All about Rhyolite and Picrite Properties

Know all about Rhyolite and Picrite properties here. All properties of rocks are important as they define the type of rock and its application. Rhyolite and Picrite belong to Igneous Rocks.Texture of Rhyolite is Aphanitic, Glassy, Porphyritic whereas that of Picrite is Earthy, Rough. Rhyolite appears Banded and Picrite appears Rough and Shiny. The luster of Rhyolite is earthy while that of Picrite is subvitreous to dull. Rhyolite is available in grey, white, light black colors whereas Picrite is available in black, brown, green, grey, pink, white, yellow colors. The commercial uses of Rhyolite are gemstone, laboratory bench tops, jewelry and that of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo).