Today Chrissy introduced me to Tiwai Beach, a new fossicking area for me. It is located on the south side of the Tiwai Peninsula, across the water from the town of Bluff (which is about 25 kms south of Invercargill). Awarua Bay lies to the north of the peninsula. Nearby, at the end of the peninsula, at Tiwai Point, is the New Zealand Aluminium Smelter, which controls access to the beach. A permit and gate key are required so we first stopped at the smelter reception for this.
The smelter was opened in 1971 after the Manapouri power station was built to supply it with electricity. It is the largest electricity consumer in New Zealand. Wikipedia reports that the smelter uses about one third of the total electricity consumed in the South Island and 13% of the total electricity nationwide, equivalent to around 680,000 households. Wikipedia also covers economic and environmental issues related to the smelter.
Tiwai Beach is a long sweeping strip running along the south of Tiwai Pensinsula, backed by a low cliff. Chrissy and I spent just over two hours there, arriving at noon, low tide time. It was a sunny afternoon, about 17 to 18 degrees, with a light breeze. A couple of fishermen catching gurnard were the only other people there.
We walked westwards along the water’s edge where there was a good scattering of interesting stones – much larger patches lay further up the beach. Way up ahead lies a large white navigation aid for Bluff Harbour, and we turned around maybe 50 metres before reaching it.
The stones on the beach are of a good range of sizes, with the biggest being too large for tumble polishing. They tend to be bashed around a bit – often one side may be relatively smooth but the other will have chunks out of it. Nevertheless Chrissy and I managed to select enough to make our backpacks heavy. Fifteen of my finds are featured below.
White quartz is the dominant stone on Tiwai Beach – from opaque whites to transparent varieties, including smokey quartz. I collected a number of these, especially small ones useful in a tumbling barrel. There is also a wide range of quartzites here, a lot of them with green or grey-green minerals:
Other quartzites have layers or clouds of a creamy pink or white.
There was the occasional yellow quartzite similar to those I have found on Seadown Beach in Kakanui (and able to be found along the east coast of the South Island up to Birdlings Flat).
We came across some very nice dark red jaspers on Tiwai Beach, often with quartz veins. This was the biggest that I put in my bag:
Unexpectedly, I happened upon two rare small poppy jaspers today – the first below was half-buried in sand, the second lying on top of other stones:
Dark rhyolites are present at Tiwai Beach, rather plain and not as interesting as Slope Point ones, though I saw one banded rhyolite. Green argillite is present but rare – Chrissy found the only trace fossil argillite stone we came across and passed it to me.
Finally, three of my other finds, not able to be identified by myself with any certainty but their colours and patterns caught my eye:
Part 10 reports on my third visit to Gemstone Beach this trip. An Index to this Series is here.
