Types of stone

Contents 1 Introduction 2 Alabaster 3 Basalt 4 Granite 5 Limestone 6 Marble 7 Onyx 8 Quartzite 9 Sandstone 10 Slate 11 Travertine 12 Related articles on Designing Buildings Wiki

[edit] Introduction

Stone, or rock, is a natural substance that is quarried and mined from the earth and used in a variety of applications in construction, including:

• Masonry, including decorative elements such as pillars, swags and porticos.
• Floor and wall tiles and cladding.
• Paving.
• Roof coverings.
• Kitchen work surfaces and table tops.
• Bathroom counter tops, shower trays and basins.
• Fire surrounds, staircases and other decorative elements.
• Aggregate.
• Ballast.
• As a component of concrete, mortar, cement, asphalt and some bricks.

The major rock groups are igneous, sedimentary and metamorphic. The unique characteristics of stone are due to the complex geological processes that have impacted upon it, creating many different types of structure, texture and colour.

Different types of stone lend themselves to different uses depending on their characteristics. It is important to get the right advice to ensure that the correct kind of stone is used.

Different types of stone include:

[edit] Alabaster

A mineral composition of gypsum, light-coloured, translucent and soft, alabaster was commonly used in the medieval period for religious carvings, such as altars, tombs and effigies. It is now used for light fittings due to its translucent nature, but is expensive and rare. For more information see: Penarth Alabaster.

[edit] Basalt

Basalt is an igneous rock that is formed from molten rock that has solidified under pressure. It has a uniform grey colour and is very hard and compact. Its most common use is as an aggregate but polished basalt is also used for flooring, monuments and other stone objects.

[edit] Granite

Granite is an igneous rock composed of quartz, mica and feldspar. It is common and widely occurring and is nearly always massive, hard and tough which makes it suitable for applications that will require wear resistance. It can range in colour from light grey to black, pink, blue and green, according to the mineral content.

Its colours, toughness and low porosity make it a popular choice for kitchen worktops, as it is attractive and resists heat and spillages of food and drink. Internally it is also used for tiles, fireplaces, staircases, where the weight is not a problem, bar tops and table tops. It also lends itself well to use outdoors for water features, monuments and paving.

River Valley Granite worktop	Monument to commemorate the D-Day Landings in Normandy Granite water feature in Manchester development
Black granite bar top in a hotel bar

[edit] Limestone

Limestone consists of calcium carbonate formed at the bottom of shallow lakes and seas that has been compacted over time. The primary source of calcite in limestones is marine organisms although other sources do occur. The presence of these organisms means that the stone often has fossil inclusions that form an attractive feature when the stone is polished or honed. It can be categorised as either soft or hard limestone. Various colours can be found as a result of the presence of different minerals in the limestone.

Limestone lends itself to use as floor tiles throughout a building and bathroom wall tiles, shower trays, cladding and vanity tops. In addition, fireplaces and staircases are often manufactured in limestone to striking effect.

It is also frequently used in the fabric of a building such as façades, cornices, pillars and other decorative features, especially in conservation areas where traditional building materials are required, such as Portland Stone in areas of London, Bath Stone in Bath and so on.

Waterjet cut polished Thala Beige limestone tiles in an entrance hall	Grigio Perla limestone tiles with quartzite island Limestone pool surround with slate tiles on the wall
Portland Stone swags in renovation	Portland Stone frieze by Julian Opie

[edit] Marble

Marble is a metamorphic rock that is predominantly composed of calcite or dolomite crystals. It is characterised by its crystal-like texture which is formed by limestone being changed by a combination of heat and pressure. It is both hard and compact.

It has been used as a building material for centuries and is suitable for many applications. It is most often used in bathrooms, spas and so on as wall and floor tiles as well as cladding, baths, work surfaces, basins and shower trays. It is also commonly used for fireplaces, staircases and table tops. It can be used for kitchen work surfaces but will wear more than granite and is more susceptible to staining.

Bookmatched Greylac marble in hotel suite	Marble artwork by Tom Phillips in St Georges Chapel, Westminister Cathedral
Water jet cut inlaid marble floor	Arabescato marble staircase and hall floor with Nero Marquina border Daino Reale marble basins

[edit] Onyx

Onyx is formed of parallel bands of chalcedony in alternating colours. It is cryptocrystalline and consists of fine intergrowths of quartz and moganite. It is available in many colours and is often used to create walls with light behind them due to its translucent nature.

Onyx bar top in Emirates Airlines Airbus A380

[edit] Quartzite

Quartzite is a metamorphic rock which is formed from pure quartz sandstone as a result of heating and pressure. Quartzite is very hard and more resistant to staining than granite. Because of this it is highly prized for use as kitchen countertops, but it is expensive as there are not many deposits suitable for use in this way. Other uses include wall and floor tiles and stairs. Crushed quartzite is also used as railway ballast and to produce industrial silica sand.

Bianco Lasa quartzite counter tops

[edit] Sandstone

Sandstone is composed of quartz particles that have eroded from other rocks, commonly granite, and cohered together with natural cement minerals in ground water before being compacted. The stone’s colour depends on the colour of the sand but tends to warm reds, yellows and oranges. It is often used for building and paving materials and other outdoor uses.

Sandstone balls fabricated as garden ornaments

[edit] Slate

Slate is a fine-grained metamorphic rock that is formed when sedimentary rock such as shale is subject to high pressure. Slate is strong and has very good weather resistance as well as low water absorption, meaning that it withstands freezing temperatures well. It is easy to split into sheets and is a common roof covering. Internally its most frequent uses are as floor tiles, hearths and kitchen worktops.

The compass rose of the Longitude Dial at Hatfield House fabricated in granite and slate by stoneCIRCLE.

[edit] Travertine

Travertine is a type of limestone that is formed by rapid precipitation of calcium carbonate, most commonly at the mouth of a hot spring. It is characterised by pitted holes and troughs in its surface, although these are often filled before honing or polishing to a smooth finish. It is a popular stone for use in facades, wall cladding and flooring and to make bathroom items such as basins and stands, vanity tops, shower trays and baths.

Travertine tiles and solid travertine bathtub in a private residence.

See also: Choosing stone.

--Stonecircle

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