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
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
Discoverer
Unknown
Unknown
Etymology
From Old French esclate, from esclat (French éclat)
From old English cealc chalk, lime, plaster; pebble, from Greek khalix small pebble, in English transferred to the opaque, white, soft limestone
Class
Metamorphic Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Group
Not Applicable
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Foliated
Clastic or Non-Clastic
Color
Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue
Grey, White, Yellow
Durability
Durable
Durable
Interior Uses
Bathrooms, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Powder
Construction Industry
As Dimension Stone
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, raw material for manufacture of quicklime and slaked lime, Source of calcium
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture, Small Figurines
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
Alumina Refineries, Creating Artwork, Drawing on blackboards, Gymnasts, athletes and mountain climbers use for grip, In aquifers, Paper Industry, Production of Lime, Raw material for manufacture of quicklime, slaked lime, Soil Conditioner, Whiting, Whiting material in toothpaste, paint and paper
Types
Not Available
Not Available
Features
Easily splits into thin plates, Surfaces are often shiny, Very fine grained rock
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
Archaeological Significance
Famous Monuments
Data Not Available
Data Not Available
Famous Sculptures
Data Not Available
Data Not Available
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.
Chalk is formed from lime mud, which accumulates on the sea floor which is then transformed into rock by geological processes.
Mineral Content
Apatite, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon
Calcite, Clay, Clay Minerals, Quartz, Sand
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Ca, NaCl, CaO
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Not Applicable
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
Grain Size
Very fine-grained
Very fine-grained
Fracture
Splintery
Not Available
Streak
Light to dark brown
White
Porosity
Less Porous
Highly Porous
Compressive Strength
Not Available
Cleavage
Slaty
Non-Existent
Specific Gravity
2.65-2.8
2.3-2.4
Transparency
Opaque
Opaque
Density
2.6-2.8 g/cm3
2.49-2.50 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
China, India, Turkey
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
Africa
Not Yet Found
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
Europe
Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom
England, France, Germany, Spain, United Kingdom
Others
Arctic
Not Yet Found
Deposits in Western Continents
North America
USA
Canada, USA
South America
Brazil
Colombia
Deposits in Oceania Continent
Australia
Not Yet Found
Adelaide, New Zealand, Queensland, Tonga, Victoria, Yorke Peninsula
Slate vs Chalk Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Slate vs Chalk characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Slate and Properties of Chalk. Learn more about Slate vs Chalk in the next section. The interior uses of Slate include Bathrooms, Decorative aggregates, Entryways, Floor tiles, Flooring, Homes, Hotels, Interior decoration, Kitchens and Stair treads whereas the interior uses of Chalk include Decorative aggregates, Homes and Interior decoration. Due to some exceptional properties of Slate and Chalk, they have various applications in construction industry. The uses of Slate in construction industry include As dimension stone and that of Chalk include As dimension stone, Cement manufacture, Construction aggregate, For road aggregate, Making natural cement, Raw material for manufacture of quicklime and slaked lime, Source of calcium.
More about Slate and Chalk
Here you can know more about Slate and Chalk. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Slate and Chalk consists of mineral content and compound content. The mineral content of Slate includes Apatite, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon and mineral content of Chalk includes Calcite, Clay, Clay Minerals, Quartz, Sand. You can also check out the list of all Metamorphic Rocks. When we have to compare Slate vs Chalk, the texture, color and appearance plays an important role in determining the type of rock. Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors whereas, Chalk is available in grey, white, yellow colors. Appearance of Slate is Dull and that of Chalk is Soft. Properties of rock is another aspect for Slate vs Chalk. The hardness of Slate is 3-4 and that of Chalk is 1. The types of Slate are Not Available whereas types of Chalk are Not Available. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Slate is light to dark brown while that of Chalk is white. The specific heat capacity of Slate is 0.76 kJ/Kg K and that of Chalk is 0.90 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Slate is heat resistant, impact resistant, pressure resistant, wear resistant whereas Chalk is heat resistant.