Sunday 7 March 2010 Twizel, New Zealand
It has been 3 1/2 weeks since my last post, which took the journey up to February 6, a month ago. We've just been having too much fun to keep up with the blog!
Sun 7 Feb: Arthur's Pass - Hokitika
On this day we drove from Arthur's Pass down out of the mountains to the west coast and on south to the small town of Hokitika, the jade capital of New Zealand. We stayed here until Feb. 10.
There are, I think, 16 shops and stores in town selling jade items, and several of them also have artisans carving the objects.
Jade is very important in the history of NZ because of its significance to the Maori people. Jade can be either of two minerals: nephrite or jadeite. They both come in similar green colors, as well as other colors, but they are different chemical compositions and structures. They both often contain extensive inclusions and impurities that affect the color. They both occur in metamorphic ultramafic rocks. "Metamorphic" means that the rocks could have started out as either igneous (from volcanoes) or sedimentary, but they were buried several kilometers down and subjected to high pressure and temperature, under which the original rocks underwent chemical transformation into different chemical compositions and structures - - i.e., they became new minerals, often ones that cannot be formed at the surface. They also experienced shear strain as the hot semiplastic rock was pushed around by the tectonic forces of the Earth's crust. This gave it a unique microcrystalline mesostructure that gives it its toughness. "Ultramafic" refers to the chemical elements comprising the mineral, and means relatively low in silicon and high in iron and magnesium. The result is a rock that can be both hard and tough - i.e., not easily fractured. The hardness of nephrite is about the same as the hardened steel that we use in files, and a bit softer than quartz or sand. This is an optimum quality to have if you want to make tools and weapons out of stone. The hardness means that it could be shaped and sharpened by rubbing on sandstone, but still be hard enough to use as an ax or a digging tool. The toughness means that it won't break easily like so many rocks do.
The Chinese jade that is so prominent in the asian section of museums could be either type, but authentic NZ jade is nephrite. It was called "pounamu" or "treasure" by the Maori because it was so valuable to them. It is not particularly rare, but it occurs mostly in about 5 areas in the South Island of NZ. The Maori never developed hard-rock mining, so the only nephrite they had access to was rocks and boulders discovered on the surface, usually in stream beds where they had been washed down from wherever the mother lode was. It was traded extensively and used throughout both islands of New Zealand, and served to make tools, weapons, jewelry, and ceremonial items.
Hokitika has a Carnegie Library building, which has now been converted into a museum.
It also has a very nice beach, so Paula enjoyed beachcombing.
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