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
Tachylite is a vitreous form of basaltic volcanic glass. This glass is formed naturally by the rapid cooling of molten basalt
Discoverer
Abraham Gottlob Werner
Unknown
Etymology
From Old French esclate, from esclat (French éclat)
From German Tachylite, from tachy- + Greek lutos soluble, melting
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Foliated
Vitreous
Color
Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue
Black, Dark Brown
Durability
Durable
Durable
Interior Uses
Bathrooms, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads
Decorative Aggregates, 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
Cutting Tool, Knives, Landscaping, Scrapers
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, Creating Artwork
Types
Phyllite, Schist, and Slate
Volcanic glass
Features
Easily splits into thin plates, Surfaces are often shiny, Very fine grained rock
Available in Lots of Colors and Patterns, Clasts are smooth to touch
Archaeological Significance
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.
Tachylite 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.
Mineral Content
Apatite, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon
Feldspar, Olivine
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Fe, Mg
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional 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, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Very fine-grained
Medium to Fine Coarse Grained
Fracture
Splintery
Conchoidal
Streak
Light to dark brown
Vermilion
Porosity
Less Porous
Less Porous
Specific Gravity
2.65-2.8
2.4
Transparency
Opaque
Opaque
Density
2.6-2.8 g/cm3
3.058 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Turkey
Cambodia, Russia, South Korea
Europe
Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom
England, Germany, Hungary, Iceland, Scotland, Sweden
Others
Arctic
Hawaii Islands
Deposits in Western Continents
Deposits in Oceania Continent
Slate vs Tachylite 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 Tachylite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Slate and Properties of Tachylite. Learn more about Slate vs Tachylite 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 Tachylite include Decorative aggregates and Interior decoration. Due to some exceptional properties of Slate and Tachylite, they have various applications in construction industry. The uses of Slate in construction industry include As dimension stone and that of Tachylite include Cutting tool, Knives, Landscaping, Scrapers.
More about Slate and Tachylite
Here you can know more about Slate and Tachylite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Slate and Tachylite 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 Tachylite includes Feldspar, Olivine. You can also check out the list of all Metamorphic Rocks. When we have to compare Slate vs Tachylite, 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, Tachylite is available in black, dark brown colors. Appearance of Slate is Dull and that of Tachylite is Glassy. Properties of rock is another aspect for Slate vs Tachylite. The hardness of Slate is 3-4 and that of Tachylite is 5.5. The types of Slate are Phyllite, Schist, and Slate whereas types of Tachylite are Volcanic glass. 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 Tachylite is vermilion. The specific heat capacity of Slate is 0.76 kJ/Kg K and that of Tachylite is 0.56 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 Tachylite is heat resistant, impact resistant, wear resistant.