The color of slate is determined by its mineral composition. Slates usually range from shades of light to dark grey in color. However, in some areas of slate industry such as in the town of Granville in New York, colored slate can be obtained. It can occur in various shades of green, red, black, purple, and brown.
If hematite is abundant, a slate is usually reddish in color. Chlorite produces green slate, while sericite produces bluish-grey slate. Carbonaceuous materials make slate appear darker grey or black, while limonite makes it yellowish-brown.
Slate is formed through the regional metamorphosis of mudstone or shale under low-pressure conditions. When shale or mudstone is exposed to heavy pressure and heat from a tectonic plate activity, its clay mineral components metamorphose into mica minerals. Mica minerals such as biotite, chlorite, and muscovite, are the main components of slate. One unique characteristic of slate is that it is formed through the process of foliation, which refers to the repetitive lamination of metamorphic rocks caused by shearing forces or differential pressure.
Layers of rocks are then formed perpendicular to the direction of the pressure of metamorphic compression. This gives slate its ability to cleave along flat planes.
It is considered as the finest grained foliated metamorphic rock, having 0. The hardness of minerals is measured through the Mohs scale. This 1 to 10 scale has been widely used in mineral identification since The Mohs scale is a comparative tool, where it measures the hardness of a material by determining which other material can scratch it.
For example, if stone A can scratch stone B, while stone B cannot scratch stone A, then A is a harder material and ranks higher on the scale.
If they can scratch each other, then they are given the same rank and are considered to have the same hardness. Slate is considered to be in between 2. However, the use of the term to refer to shale has resulted to confusion, as slate itself is actually different from shale. In s, a small piece of slate affixed in a wooden frame was widely used by elementary school students for their writing activities or arithmetic problems.
People then used a small pencil made of slate, soapstone, or clay to write on the writing slate. It could be wiped clean with a cloth. The parallel alignment of minerals gives the rock the ability to break evenly along the planes of foliation.
This is called the slaty cleavage, which gives the rock the ability to split into very thin layers. There is approximately 0.
Slate, therefore, can be produced in thin sheets that are mostly used in construction and manufacturing industries. What is Slate Used For?
Slate can contain trace metals within the stone, and uneven heating in a microwave or oven may cause the slate to break You can pre-heat your Slate p late in a warming oven at F or less.
Below are some fun uses you can try for your slate! Slate is well known for its use as for serving food, but there are many other great uses for this unique natural stone, that makes it the perfect slate cheese board.
The reason that slate is widely used for serving food is three-fold. First, and most notable, is that the dark color of the natural stone brightens your cheeses and other foods making your dishes or offerings more vibrant and attractive.
This confusion of terms partially arises from the fact that shale is progressively converted into slate. Imagine driving your car eastwards in Pennsylvania through areas of increasing metamorphism, starting where the rock is definitely "shale" and stopping to examine rock at each outcrop. You will have a difficult time deciding where on that route "shale" has been converted into "slate. In the coal mining industry of the Appalachian Basin, the word "slate" is still used by many miners in reference to the shale that forms the roof and floor of a mine, and for fragments of shale that are separated from the coal in preparation plants.
Experienced miners train newer miners, and archaic language is passed along. In the s, elementary school students used a small piece of slate mounted in a wooden frame for writing practice and arithmetic problems. Writing was done with a small pencil made of slate, soapstone, or clay. The slate could be wiped clean with a soft cloth. Small slates were also used in schools and businesses to list daily events, schedules, menus, prices, and other notices.
Today, over years after writing slates started to disappear from schools, the word "slate" is still used in phrases such as "clean slate," "wipe the slate clean," "slated for today," "put it on the slate" and more. Slate siding: Slate is sometimes used as facing stone on building exteriors.
Foliation in slate is caused by the parallel orientation of platy minerals in the rock, such as microscopic grains of clay minerals and mica. These parallel mineral grain alignments give the rock an ability to break smoothly along planes of foliation.
People exploit this property of slate to produce thin sheets of slate that are used in construction projects and manufacturing. Slate tile flooring: Slate is a durable rock that is suitable for use as flooring, stair treads, sidewalk slabs, and patio stone. It is also produced in a variety of colors that allow it to be incorporated into a variety of design projects. Shown above are multi-color flooring tiles. Most of the slate mined throughout the world is used to produce roofing slates.
Slate is also used for interior flooring, exterior paving, dimension stone, and decorative aggregate. Small pieces of slate are also used to make turkey calls. The photos on this page document several uses of slate. Historically slate has been used for chalkboards, student writing slates, billiard tables, cemetery markers, whetstones, and table tops.
Slate is ecologically sound and its use does not harm the environment. There are various types of slate roof coverings, including triple, double, scales, French, triple rounded without corners and Abbadini. Slate is used for external flooring, internal flooring and cladding. Slate floors are commonly laid in outdoor porches, basements, bathrooms and kitchens.
Internal slate floors are durable, versatile and elegant. They allow homeowners and interior decorators to create unique, one-of-a-kind environments. Internal slate floors are available in a wide range of honed finished tiles, natural patterns natural cleft and colors, including green, black, gray, red and purple — accenting a space with unmatched style.
Slate floors are durable, nonporous, and require little maintenance. External slate flooring can be made with either random slate or slate tiles. Random slate comes in various shapes, such as trapezoids and parallelograms and offers a more natural look.
Tiles make for a more finished-looking space. Slate rock is used in various residential and commercial landscaping projects for its weather-resistant and pollution-resistant properties. It is used to pave paths, surround swimming pools, cover outer walls, make risers and treads on stairs, and even for patios.
Slate stone is chiseled to make fountains, used in both traditional and contemporary styles. The smooth playing surface of a billiard table is made from quarried slate.
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