Chì sò e petre naturali più morbidi è induve ponu esse aduprati ? petra di u paisaghju

Perchè sò certi petre naturali 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.

Petri irregolari

Roccia sedimentaria

Calcariu, arenaria è shale sò i tipi più cumuni di roccia sedimentaria. Quessi sò stati furmati da una pressione tremenda, annantu à milioni d'anni, chì portanu à u sedimentu chì era cascatu à u fondu di l'oceanu.

Ardesia

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.

Calcariu

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.

Sandstone

A arenaria era probabilmente a petra di custruzzione più usata prima di u 1800, per tuttu, da i ponti à l'edificazioni maestose. Comu pò esse inferitu da u so nome, hè furmatu quandu a sabbia, a materia urganica, a calcite è una varietà di altri minerali sò stati fusi inseme sottu una pressione incredibile annantu à i millenni. Disponibile cù una struttura grossa o fina è tradiziunale furnitu in un finitu opaco. Principalmente crema, rossu o grisgiu in u Regnu Unitu, u so culore dipende di i minerali supplementari cuntenuti in questu. La silice confère la blancheur, tandis que le fer donnera une teinte brun-rouge. I so principali duminii d'applicazione sò i muri è i pavimenti, o pavimenti esterni.

Marmura

U marmura hè un derivativu di calcariu, furmatu da a metamorfosi di u caldu colossale è a prissioni annantu à milioni d'anni. Ancu s'ellu hè relativamente morbidu cumparatu cù altre petre, u marmura tende à pulisce incredibbilmente bè. Tradizionalmente, u marmura hè adupratu in e porte è aiuta à creà un finitu high-end.