Finding Flint in NZ

[Colin & Lynlee]

Thought you might like to read this small reference from http://www.teara.govt.nz/EarthSeaAndSky/Geology/Gemstones/2/en:

Chert, flint and jasper
Chert, flint and jasper are opaque forms of silica that are usually formed as bands or nodules in sedimentary rocks. Chert is yellow to brown. Flint is a hard variety of chert, found as nodules in chalky limestone. It can be trimmed and shaped, and was occasionally used by Māori for making tools. Pebbles of chert and flint can be picked up on beaches near Kaikōura and along the eastern side of the North Island. Jasper is red or multi-coloured, and commonly occurs with volcanic rocks.

Ballast at Balaena Bay
Flint is common on southern English beaches and was often used as ballast for ships travelling to New Zealand. English flint pebbles are now found in several New Zealand harbours, where they were dumped when cargo was loaded and the stone was no longer needed to keep the ship stable. Balaena Bay in Wellington Harbour is a favourite place for rockhounds.


I have a few stones I picked up from Kaikoura Beach. I cannot identify one form from another but I can bring them to Easter Camp. I did choose them for being pretty at the time, not cause I was looking for flint or chert.

Lynlee

[ann dugmore]

Will have a few pieces of REAL flint for sale at NAAMA 2009. How about a fire-lighting competition? Its all right I'm crap at it too!
Ann

[Robbo]

I got frowned on for suggesting that, but I still think it's a great idea.

Hope it works out well for you Ann.

[Rhiannon]

I believe that any type of chert or jasper will work for making fire. Brown cherts and red jaspers can be found over much of the country's stone beaches. The use of the word 'flint' is usually reserved for chert found in chalk. The best quality has almost no internal structure (monocrystalline). The red of jasper comes from association with volcanic rocks.

Geologically.... The red jasper comes from the oldest part of the basement terrane called the Waipapa/Rakaia Terrane, found in Coromandel and the east side of Auckland and Northland, parts of Wellington-Kapiti Coast, and from Christchurch adn Canterbury Plains. It was formed near a mid-oceanic spreading ridge halfway to South America, in the Triassic-Permian (several tens of millions of years before T Rex). It is formed from siliceous ooze on the sea floor (mostly diatoms, single celled plankton).

From a more practical assessment, you can tell the difference between calcite, quartz and chert by the smell made by hitting them with a steel hammer. The chert smells a bit like burning. If you got a flattish piece of chert and hit it at the right shallow angle with a steel hammer, you get sparks.

If anyone wants to be taught what chert looks like, PM me before a NAAMA or Taupo/Harcourt Park and I'll bring some chert, flint and jasper to be looked at.

[ann dugmore]

I still have a fair amount of small flint pieces from the limestone downs in Wiltshire for sale which I will bring to Taupo. Only large enough for fire lighting NOT flint knapping!