Hebel was developed by Josef Hebel, a German building contractor, who saw a need for an alternative, strong, cost effective, building material. Hebel (or aerated concrete) is a concrete medium. It is created by mixing sand, lime and cement with aluminium powder. This causes a foaming chemical reaction between the different compounds to form air cells in the concrete which increases its volume by 500%. The hebel mix is then placed in an autoclave (steam curing in a pressurized chamber) which hardens the material.
Hebel is mainly used as a construction material. However because it is very easy to manipulate it is a perfect medium for carving.
Hinuera stone is a unique natural volcanic stone quarried from the hills in Hinuera, Waikato, New Zealand. It is the only resource of its kind in the Southern Hemishere. Hinuera ignimbrite (often marketed as Hinuera stone) is a yellow-cream to pale-brown ignimbrite containing angular fragments of pumice in a fine-grained matrix of volcanic ash. It is still quarried today, and widely used for cladding buildings in the North Island.
Oamaru stone is a limestone mined at Oamaru in the South Island.