CALES SON AS PEDRAS NATURAIS MÁIS BRANDES E ONDE SE PODEN UTILIZAR? pedra paisaxística

Por que son algúns pedras naturais considered to be soft when they all appear to be hard? The answer lies within ‘relative’ hardness. Mohs scale of hardness was invented in 1812 and compares the relative hardness of ten minerals. Diamond is the hardest and rates a 10, while granite is the toughest natural stone at 6. Limestone comes in at 3 as does its metamorphic counterpart, marble. Softer stone is easier to dress or carve but does not wear or weather quite as well as harder stone. Here we discuss some of the more popular soft stones along with suitable applications.

Pedras irregulares

Rocha sedimentaria

As pedras calizas, areniscas e xistos son os tipos máis comúns de rochas sedimentarias. Estes formáronse a través dunha tremenda presión, ao longo de millóns de anos, que incidiu sobre os sedimentos que caeran ao fondo do océano.

Lousa

The layers in slate are described as being “foliated” and they are easily split apart to create whatever thickness is required. UK slate is considered to be hard and was traditionally used as roofing, while soft slate is found in China, Spain, Italy and the USA. With a broad range of natural slate colours, a multiple array of designs can be achieved, from contemporary to classic, rustic to refined. Slate is often recommended for high traffic areas, thanks to its remarkably durable composition. It is also non-porous and does not easily react with acid liquids. It is fire proof, weather resistant and achieves good slip resistance dues to its riven finish.

Pedra calcaria

Limestone is a very common building material and is formed mainly from the mineral calcite, derived from the calcium in bones and seashells deposited over the millennia and forced together through pressure. While it also contains magnesium, it is harder and more weather resistant, and can also be polished. Portland stone from the eponymous island in Dorset is probably the single most famous type of limestone and was used to build many of London’s great buildings. It is used for external cladding as well as paving, fireplaces and other internal and external decorative features. Its soft colours are its trademark visual attributes.

Arenisca

A pedra arenisca foi probablemente a pedra de construción máis usada antes de 1800, para todo, desde pontes ata edificios señoriais. Como se pode deducir do seu nome, fórmase cando a area, a materia orgánica, a calcita e unha variedade de outros minerais se fundiron baixo unha presión incrible ao longo dos milenios. Dispoñible cunha textura grosa ou fina e tradicionalmente ofrécese nun acabado mate. Principalmente crema, vermella ou gris no Reino Unido, a súa cor depende dos minerais adicionais que contén. A sílice dá brancura, mentres que o ferro dará un tinte pardo avermellado. Os seus principais ámbitos de aplicación son os muros e pavimentos, ou a pavimentación exterior.

Mármore

O mármore é un derivado da pedra calcaria, formada pola metamorfose da calor colosal e da presión ao longo de millóns de anos. Aínda que é relativamente suave en comparación con outras pedras, o mármore tende a pulir incriblemente ben. Tradicionalmente o mármore úsase nas portas e axuda a crear un acabado de alta gama.