Pounamu

Pounamu or greenstone are terms for several types of hard and durable stone found in southern New Zealand. They are highly valued in New Zealand, and carvings made from pounamu play an important role in Māori culture. 
Geologically, pounamu are usually nephrite jade, bowenite, or serpentinite. The Māori classification of pounamu is by colour and appearance. The main classes are , , , and . The first three are nephrite jade, while is a form of bowenite.
In modern usage almost always refers to nephrite jade. Pounamu is generally found in rivers in specific parts of the South Island as nondescript boulders and stones.
Significance to Māori.
Pounamu plays a very important role in Māori culture and is a (treasure). It is and has been an important part of trade between the South Island (tribe) and other . Adze blades made from pounamu was desired for carving of wood, and even with the arrival of metal tools pounamu tools were used. These were often reworked into and other when they were no longer useful for carving wood. After the arrival of to South Island in the middle of the 18th-century production of pounamu increased. Pounamu crafting and trade was important to the economy of .
Pounamu increase in (prestige) as they pass from one generation to another. The most prized are those with known histories going back many generations. These are believed to have their own and were often given as gifts to seal important agreements. 
Pounamu include tools such as (adzes), (chisels), (gouges), (knives), scrapers, awls, hammer stones, and drill points. Hunting tools include (fishing hooks) and lures, spear points, and (leg rings for fastening captive birds); weapons such as (short handled clubs); and ornaments such as pendants (, and ), ear pendants ( and ), and cloak pins. Functional pounamu tools were widely worn for both practical and ornamental reasons, and continued to be worn as purely ornamental pendants () even after they were no longer used as tools.
Pounamu is found only in the South Island of New Zealand, known in Māori as ('The [land of] Greenstone Water') or ('The Place of Greenstone'). In 1997 the Crown handed back the ownership of all naturally occurring pounamu to the South Island (or Kai Tahu), as part of the Ngāi Tahu Claims Settlement.
Geological formation and location.
Pounamu has been formed in New Zealand in four main locations; the West Coast, Fiordland, western Southland and the Nelson district. It is typically recovered from rivers and beaches where it has been transported to after being eroded from the mountains. The group of rocks where pounamu comes from are called ophiolites. Ophiolites are slices of the deep ocean crust and part of the mantle. When these deep mantle rocks (serpentinite) and crustal rock (mafic igneous rocks) are heated up (metamorphosed) together, pounamu can be formed at their contact. 
The Dun Mountain Ophiolite Belt has been metamorphosed in western Southland and pounamu from this belt is found along the eastern and northern edge of Fiordland. The Anita Bay Dunite near Milford Sound is a small but highly prized source of pounamu. In the Southern Alps, the Pounamu Ultramafic Belt in the Haast Schist occurs as isolated pods which are eroded and found on West Coast rivers and beaches.
Modern use.
Jewellery and other decorative items made from gold and pounamu were particularly fashionable in New Zealand in the Victorian and Edwardian years in the late 19th and early 20th century. It continues to be popular among New Zealanders and is often given as gifts. In 2011, the New Zealand Prime Minister John Key presented the President of the United States Barack Obama a (a type of Māori weapon) created from pounamu carved by New Zealand artist Aden Hoglund. 
An exhibition curated by Te Papa in 2007 called showcased 200 pounamu items from their collections and linked New Zealand and China through both the geographical location of nephrite and also the high level of artistry achieved in ancient China and then thousands of years later amongst Māori. The exhibition marked 40 years of diplomatic relations between countries when it toured to five venues in China in 2013.
In the 2016 animated movie "Moana" the central premise is to return the stolen heart of Te Fiti which is manifest in a pounamu stone amulet.
Fossicking for Pounamu is a cultural activity in New Zealand and allowed on designated areas of the West Coast of the South Island () and is limited to what can be carried unaided; fossicking elsewhere in the tribal area is illegal, while nephrite jade can be sourced legally and freely from Marlborough and Nelson. In 2009 David Anthony Saxton and his son Morgan David Saxton were sentenced to two and a half years imprisonment for stealing greenstone, with a helicopter, from the southern West Coast.