Another Visit to Birdlings Flat, Late June 2016 – Part Three: Seven Types of Stones Collected

During the six to seven hours spent at Birdlings Flat and nearby beaches during two and a half days at the end of June, I collected just over eight kilograms of stones. These consisted of a number of different types of stones. After my two previous visits, I had a good idea of what I was looking for, based on the results of some tumble polishing as well as my own preferences. There are many greywacke stones on the beach, the common grey beach stones of New Zealand, as well as a wide range of other types.

Following are listed the seven types of stones I collected during this visit:

Yellow-patterned Quartzite; Red Jasper; Agates; Green (Quartzite?); Patterned; White Quartz and Other Light-Coloured; Others.

Yellow-patterned Quartzite – This can easily be found at Birdlings Flat and is perhaps my favourite stone from there. I discovered a small boulder of it, that filled both my hands – which I had to leave at the beach. I have brought home at least two hand-sized specimens. There are a number of subtle colour variations of this stone, the best seeming to be a clear to light coloured quartzite with curtains or swirls of “gold foil” throughout it. The intensity of the gold/yellow can vary from stone to stone as can the patterns inside it. During this trip, I sought to collect stones exhibiting these variations. 

 Red Jasper – Red jasper stones can often be found on South Island beaches. They are reasonably easy to find at Birdlings Flat, where they can be of good size and quality. Many jasper stones have silica veins, sometimes bright red veins as well, and some other mineral staining can be present. They can be brittle, with chips and pits, making them difficult to smooth and polish.

 Agates – Birdlings Flat is well-known for its agates. A wide range of sizes, shapes and types can be found. It took me a while before I learned to spot them. The best way is to look towards the sun and your eye will be drawn to the light shining through them, even amidst a whole mass of other types of stones. On this trip, I found my largest agate so far, and a very small one with a green staining.

Green (Quartzite?) – One of the interesting types of stones to be found at Birdlings Flat is green and I suspect is a type of quartzite. Again, there is a great diversity of them, from pale green through to lime green through to darker greens. I find them quite attractive and relatively easy to spot.

Patterned – I find myself drawn to even greywacke stones and other grey (or common coloured) stones if they have veins of white quartz through them or if they display layer patterns.  

White Quartz and Other Light-Coloured – Going through the stones I collected, I find there are a number of white quartz stones and other white or light-coloured stones. These tend to catch my eye on any beach, standing out from the sand or the predominant grey of the most common stones on South Island beaches. I have learned to be more restrained in my collection of white quartz as it is easy to spot it and can soon mount up in the collection bag.

  Others – What’s left in my collection bag after the rest have been taken away: 

Another Visit to Birdlings Flat, Late June 2016 – Part Two: Birdlings Flat Gemstone Museum Again

The second day of our visit to Birdlings Flat, Petra and I visited Vince and Colleen Burke’s Gemstone and Fossil Museum on Hillview Road. This time, Colleen opened up the Museum for us and we got to talk with her about Birdlings Flat and the stones in the collection. Vince then took over from her after about 15-20 minutes. Petra bought a good-sized batch of agatised wood which we will have a go at polishing sometime. Vince generously gave her three pieces of polished agatised wood, to give her an idea of the end product of polishing.  Agatised wood is a form of petrified wood and is in effect a fossil. It forms when plant material is buried by sediment and thus protected from the decaying action of oxygen and organisms. Groundwater rich in dissolved solids flows through the sediment replacing the original plant material with minerals such as silica, calcite and pyrite or another inorganic material such as opal. The result is a fossil of the original woody material that often shows preserved details of the bark, wood and cellular structures. “Agatised” wood is wood that has been replaced by agate, a form of chalcedony or microcrystalline quartz.

After about 30 to 40 minutes at the Museum, we moved onto the beach and spent nearly three hours fossicking for stones, walking eastwards right up to the end of the beach where it butts up against Banks Peninsula. We collected a few kilograms of stones, and returned the next day to collect even more. The next post will look in more detail at the variety of these stones.  

Another Visit to Birdlings Flat, Late June 2016 – Part One: Taumutu

I introduced my wife Petra to Birdlings Flat. We started with a visit to Taumutu, at the southwest end of Kaitorete Spit (although Kaitorete Barrier Beach is a more accurate term for this enormous 25 kilometres long gravel bank).  Taumutu is a rural district on the coast, the other end of Lake Ellesmere from the Birdlings Flat village.

The late winter’s afternoon was cold and windy so we had to wrap up warmly when we ventured onto the beach. We spent maybe only 30 to 40 minutes there before needing to retreat to the car to escape the chilling of the onshore wind. We managed to walk up and down the beach in both directions and collect a few stones. These were similar to those found anywhere along this stretch of coastline, including quartzites and agates.