HE AHA NGA KOHAA NATURAL MAHI ANA, HEIHEA KA WHAKAMAHI? kohatu whenua

He aha etahi kohatu maori 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.

Kowhatu korikori

Toka parataiao

Ko te toka parataiao te nuinga o nga momo toka parataiao. I hanga enei na roto i te pehanga nui, i roto i nga miriona tau, e mau ana i te parataiao kua taka ki te papa o te moana.

Papapapa

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.

pākeho

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.

Te kirikiri

Ko te kirikiri pea te kohatu hanga i mua i te tau 1800, mo nga mea katoa mai i nga piriti ki nga whare rangatira. Ka taea te whakatau mai i tona ingoa, ka puta mai i te whakakotahitanga o te onepu, te mea waro, te calcite me etahi atu momo kohuke i raro i te pehanga nui i roto i nga mano tau. E waatea ana me te kakano kakano taratara, kakano pai ranei, ka tukuna i mua i te mutunga matt. Ko te kirikiri, he whero, he hina ranei i te UK, ko tona tae ka whakawhirinaki ki nga kohuke taapiri kei roto. Ko te Silica he ma, ko te rino ka puta he kara whero-parauri. Ko nga waahanga nui e whakamahia ana ko nga pakitara me nga papa, ko te whariki o waho ranei.

Mapere

Ko te mapere he whakaputanga o te kowhatu kowhatu, i hua mai i te kaahuatanga o te wera nui me te pehanga i roto i nga miriona tau. Ahakoa he ahua ngawari ki etahi atu kohatu, he pai te whakakoi mapere. Ko te mapere o mua ka whakamahia i roto i nga tatau me te awhina ki te hanga i te mutunga teitei.