QUAE SUNT MOLLIOR NATURALIS LAPIDES ET Vbi adhibeantur? landscape lapis

Quid sunt quidam lapides naturales 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.

Irregulares lapides

Saxum sedimentarium

Calcis, sandstone et shale frequentissima sunt genera sedimentarii petrae. Hi per immensam pressionem decies centena millia annorum facta sunt, quae faecis in area Oceani demissa.

Slate

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.

calcis

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

Sandstone verisimile erat lapideum ante 1800 ad usum communissimum construendum, omnia enim a pontibus ad aedificia magnifica. Ut ex eius nomine colligitur, formatur cum arena, materia organica, calcita et alia varia mineralia in millennium incredibili pressione coacta sunt. Praesto est vel crassum vel subtiliter textura et tradito suppletum in materia matta. Primum cremor, rubeus vel griseus in UK, color eius pendet a mineralibus additis in se contentis. Silica candorem tribuit, ferrum subrubicundum dabit. Praecipua eius loca applicationis sunt parietes et contabulationes, seu straturae exteriores.

Marmor

Marmor calcis derivativum est, formata per metamorphosin caloris colossalis et pressionis per decies centena millia annorum. Etsi relative mollia cum aliis lapidibus comparata, marmor tendit incredibiliter bene expolire. Marmoris institutio in ianuis adhibetur et adiuvat ad summum finem conficiendum.