Marble, Stretcher

Marble is a hard, durable, exquisite stone used in architecture and design as both internal and external finishes. Marble typically posses a white finish in its purest form owing to its calcitic carbonate makeup, although other colours are displayed due to a variety of impurities within the stone, from other mineral and rock compositions such as clay, quartz, iron oxides and graphite. Marble is rarely a dominant material in buildings due to its high cost, but can be found in ornate flooring, columns, countertops, staircases, cladding, or façade details. A metamorphic, almost crystalline state variant of limestone, marble polishes to a very high finish, becoming almost completely smooth and reflective. Limestone, a sedimentary rock, is composed from calcium carbonate, forming when other types of rock are subject to a sequence of weathering and erosion known as denudation: Mechanical weathering from ice, water flow, waves, rain, wind or thermal activity strips or grinds down parts of the origin rock, with particles being eroded, or transported away from the source area, by glaciers, rivers, wind or water. High concentrations of the particles are deposited in one area, often setting on lower land or in bodies of water. The transportation process helps round and smooth the harder particles and remove weaker grains. Calcitic minerals can also gather when left behind after bodies of water evaporate. The particles then undergo a process known as lithification over an extensive period of time, whereby particles are compacted in layers, compressed under their own weight and bound or cemented together when exposed to and combined with chemicals such as oxides or, with limestone, higher concentrations of carbonates, which helps increase the bond between the graduals and reduce the porosity of the newly formed rock. Some limestones form when calcitic minerals from plant and animal debris or remains break down, accumulate and are lithified and are known as organic sedimentary rock, occasionally containing fully intact fossils. The process of denudation, erosion and formation of the new rock is known as sedimentation. Marble is normally chemically transformed from limestone at the boundaries of convergent plates through direct exposure to the heat of the earth’s core combined with the pressure from the weight of layers above causing the calcite to recrystallise, changing the texture and characteristics of the rock, a process known as metamorphosis. Metamorphosis can also occur when limestone or dolomite rock is exposed to magma from the earth’s core when it punctures through to form magma chambers, or ruptures the earth’s surface and discharges under pressure. Immediately after the transition, calcite crystals are small, but grow in size to become interlocked, hiding any sedimentary structures and fossilised remains commonly found in limestone. Marble undergoes a unique transformation uncommon to other rocks formed by metamorphism whereby it doesn’t form in layers, or foliate, leaving a pristine, unblemished, seamless surface appearance. Minerals present in the limestone pre-metamorphosis change in structure like the calcitic content: Clay transforms to complex silicates, further solidifying the new rock. Due to the locations and circumstances in which marble transitions from limestone, it is normally found in large, geographically concentrated quantities, allowing it to be mined efficiently. Marbles can be used in architecture as aggregate in roads, hardcore and as a site levelling base in construction projects, or cut and highly polished for a smooth finished, dimensioned stone, varying in colour from pure white muddy or hazy creams, beiges, pinks, greys and browns depending on their chemical compositions. Higher proportions of calcium and low ratios of magnesium, as found in calcite limestone, tend to be lighter and contain more silvers and whites; increases in magnesium content provide a balance of light, cool greys with sandy blonde or pink hues; while dolomitisation occurs when magnesium-rich groundwater reacts with calcite to produce dolostone or dolomite rock, possessing darker greys or orange and brown shades owing to its higher levels of magnesium. These colours are then embeded as streaks, veins or overall pigments in marble when it transforms. Marble is most commonly associated with sculptures, ornaments, monuments and highly decorative or elaborate architectural works, owing to its relatively soft hardness rating, fine grain and uniform properties throughout, making it easy to carve and work, alongside its pristine, pearly white, translucent, virtually flawless surface which allows light to penetrate and reflect from within, creating a gentle, warm, radiant shine; enhancing the sculpture's divine appearance. Its favourable mechanical characteristics, workability and gorgeous, refined appearance are desirable factors for its specification as headstones in cemeteries, cutting more favourably and therefore economically, appearing brighter and more elegant while suffering less from the effects of weathering than other stones, particularly from acidic pollutants and rain, due to its high calcite and carbonate content. As a dimensioned stone, finished, sawn marble can be used for landscaping furniture; as floor and wall tiles; as sheets, panels, blocks, bricks and slabs for external façades, cladding systems and facing stone; as feature elements or highlights like countertops, stairs, fireplace, window and door surrounds, or in kitchens and bathrooms, provided the marble is of sufficient grade to prevent water ingress, from smaller scale domestic properties to high quality office, commercial, hotel, hospitality or civic interiors and fit-outs. It is generally better suited to finish applications and light foot traffic areas than as flooring in high traffic areas as it damages and marks quicker and easier than most stones. Synonymous with class and style in both historic and contemporary settings, marble is commonly used in decorative applications and as an extravagant interior trim or bathroom finish, adding a bright and dramatic touch to spaces. This marble texture is a pale, beige-white with a creamy pink tint. Thin, faint, black veins and sultry, deep, mysterious navy blue streaks and patches are evident, appearing like a stormy ocean. The restrained, muted white field creates a cool, weathered, mature, vast feel, with a subtle warmth balancing the surface in the form of rust or orange-brown deposits, likely from clay or iron oxide minerals. This marble texture would be an excellent pairing to compliment historic, traditional designs or as a standout, accent material in contemporary applications. Marble is often replaced by Quartzite, another metamorphic stone of similar appearance but higher durability, or can be imitated by Porcelain tiles for those who wish to specify a more economical, durable material which closely resembles the feel and aesthetic of marble. The appeal of genuine marble is that each stone or slab is unique in pattern and colour, is free of stratification or clear layering for a homogenous look, while developing a patina as it ages, maturing and bedding into its environment.