CARVING OAMARU STONE

The stone I use is Oamaru stone or Limestone. Because it can be readily shaped, Oamaru stone is a favourite material for stone carvers and sculptors in New Zealand.

The white, easily sawn Oamaru Stone is known to geologists as Totara Limestone. When Totara Limestone was formed, some 35 - 40 million years ago, the sea covered about 200 sq km of North Otago, reaching as far west as Aviemore. Hard calcareous shells of marine animals and plants living in the shallow warm seas built up a thick blanket of limey sediment on the sea floor. Over millions of years the soft sediment became lithified (hardened into rock ), and was eventually lifted above sea level.

This Limestone is mostly formed of sand-sized bryozoan fragments, with vast numbers of micro fossils such as foraminifera, and occasional larger fossils of molluscs, brachiopods, corals and echinoderms, and sometimes penguin or whale bones and sharks teeth.

Occassionally a stone carver may come across a brown or soft spot, it is believed to be a branch or other form of wood trapped within the stone.

You often don’t know what you will find in the stone until you begin your work. In most cases you simply accept any variations the stone throws at you and work it in or around it. And there are ways to cosmetically cover any blemishes if you think it necessary.

Care of your Sculpture

Oamaru stone is very porous, so water soaks in easily. Deterioration will occur over a very long period, as water freezing and expanding may affect delicate parts of a sculpture. Sealing the sculpture with a silicon or water based stone sealant will prevent moisture entering the stone and still allow the stone to “breathe”.

The immediate effect of sealing the stone is to emphasize its natural yellowish colouring and highlight any layers or grain within the stone. A light sanding when the sealant is dry will return the stone to its whitish luster.

Over time, moss or mould may appear on the stone (some people prefer that look and apply yoghurt to encourage it), but a spray with “30 seconds” or cleaning product, and a quick rinse will restore its original appearance.

READ STONE CARVING STORIES

PLEASE VISIT MY GALLERY

CONTACT BRETT KENO