Definition
Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism
Websterite is ultramafic and ultrabasic rock that consists of roughly equal proportions of orthopyroxene and clinopyroxene. It is a special type of pyroxenite.
Origin
England
Webster, North Carolina
Discoverer
Unknown
Unknown
Etymology
From Old French esclate, from esclat (French éclat)
From the town of Webster located in North Carolina
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Group
Not Applicable
Plutonic
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Foliated
Clastic, Granular, Phaneritic, Porphyritic
Color
Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue
Black to Grey, Bluish - Grey, Dark Greenish - Grey, Green, Light Greenish Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull
Layered, Banded, Veined and Shiny
Interior Uses
Bathrooms, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads
Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts
Commercial Uses
Blackboards, Commemorative Tablets, Laboratory bench tops, Standard material for the bed of Billiard table, Standard material for the beds of Pool and Snooker table, Tombstones, Used in aquariums, Writing Slates
Cemetery Markers, Commemorative Tablets, Creating Artwork, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Types
Not Available
Not Available
Features
Easily splits into thin plates, Surfaces are often shiny, Very fine grained rock
Generally rough to touch, Is one of the oldest rock
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Data Not Available
Data Not Available
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Used
Not Yet Used
Formation
Slate is a low grade metamorphic rock that is generally formed by metamorphosis of mudstone or shale, under relatively low pressure and temperature conditions.
Websterite can be formed as cumulates in ultramafic intrusions by accumulation of pyroxene crystals at the base of the lava chamber.
Mineral Content
Apatite, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon
Amphibole, Augite, Bronzite, Chromite, Diopside, Enstatite, Garnet, Hornblende, Hypersthene, Magnetite, Pyroxene
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Burial Metamorphism, Impact Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Grain Size
Very fine-grained
Coarse Grained
Fracture
Splintery
Uneven
Streak
Light to dark brown
White, Greenish White or Grey
Porosity
Less Porous
Less Porous
Luster
Dull
Dull to Vitreous to Submetallic
Compressive Strength
Not Available
Toughness
1.2
Not Available
Specific Gravity
2.65-2.8
3.2-3.5
Transparency
Opaque
Opaque
Density
2.6-2.8 g/cm3
3.1-3.6 g/cm3
Specific Heat Capacity
Not Available
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Turkey
India, Russia
Africa
Not Yet Found
South Africa
Europe
Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom
Germany, Greece, Italy, Scotland, Turkey
Deposits in Western Continents
North America
USA
Canada, USA
South America
Brazil
Brazil, Colombia, Venezuela
Deposits in Oceania Continent
Australia
Not Yet Found
New Zealand, Queensland
All about Slate and Websterite Properties
Know all about Slate and Websterite properties here. All properties of rocks are important as they define the type of rock and its application. Slate belongs to Metamorphic Rocks while Websterite belongs to Igneous Rocks.Texture of Slate is Foliated whereas that of Websterite is Clastic, Granular, Phaneritic, Porphyritic. Slate appears Dull and Websterite appears Layered, Banded, Veined and Shiny. The luster of Slate is dull while that of Websterite is dull to vitreous to submetallic. Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors whereas Websterite is available in black to grey, bluish - grey, dark greenish - grey, green, light greenish grey colors. The commercial uses of Slate are blackboards, commemorative tablets, laboratory bench tops, standard material for the bed of billiard table, standard material for the beds of pool and snooker table, tombstones, used in aquariums, writing slates and that of Websterite are cemetery markers, commemorative tablets, creating artwork, laboratory bench tops, jewelry, sea defence, tombstones.