“Well that was hard!” 36 Milestones for a Completed Thesis – Part Two: Stones 11 to 22 (Gemstone Beach)

These 36 tumble-polished stones mark the completion by Lynley Uerata of her doctoral degree. Her doctoral thesis is entitled “Insecure, Unpredictable, Hoping to Survive: Four Cases of Māori People Living Precariously in Hamilton, Aotearoa New Zealand” (you can view it here).  A doctoral thesis is a report on a research project that has taken a number of years and it is often a significant life achievement. So I am giving Lynley one polished Tumblestone as a milestone for each year of her life so far. These 36 stones, from four different beaches, will be presented in three Posts. The first Post in this Series, dealing with 10 stones from Timaru South and Kakanui, is here. This Post features the 12 stones from Gemstone Beach. Each stone provides some metaphorical parallel to the process of thesis research.

Gemstone Beach, at Orepuki on Foveaux Strait, is probably the most well-known stone fossicking beach in the lower South Island. It lies on the coast of Te Waewae Bay, to the east of the Waiau River mouth. The Waiau River brought down many rocks and stones from further north, including the eastern Fiordland mountains. TumbleStone2 provides a detailed introduction to Gemstone Beach, which is my main fossicking beach.

Milestone #11 is a brecciated stone, with green fragments cemented in a fine red matrix. This mix of colours is unusual in my experience. The stone was January 2022 Stone of the Day #15. See this Post for some information on breccia and Gemstone Beach. Lynley’s thesis also contains a number of unusual mixes, such as its concerns with both large-scale processes and their impact on the lives of individuals.

Another January 2022 Stone of the Day is Milestone #12. It was Stone of the Day #19 and is a tiny jasper, the smallest of the 36 Milestones (see here for a Post with some detailed information on jasper). Though this stone is small, careful examination reveals interesting and intricate details. As Lynley’s thesis shows, the smallest and seemingly most innocuous of people still have much to teach others when we take a careful look at their lives.

It is interesting to compare Milestone #13 (photos immediately below) with Milestone #20 (photos further on). Both are black and white stones but their characters are quite different. Whereas Milestone #20 has well-defined white shapes in a black matrix, Milestone #13 has more cloudy white shapes that merge into the black. In many ways, this makes for a more interesting stone, drawing the eye to explore its nuances. A thesis can treat life as black and white, with clearly defined boundaries or where the boundaries are fuzzy.

Milestone #14 is a trace fossil stone, known at Gemstone Beach as a fossil worm cast stone. It is an argillite stone. Some animal once burrowed through mud or moved along the mud’s surface at the bottom of the ocean and left behind these traces. See here for some information on these stones. A thesis is like a trace fossil, a picture frozen in time of a society or one of its members. Here is what life was like at this particular point in time.

Gemstone Beach is known for its hydrogrossular garnets. Milestone #15 is a gorgeous brown hydrogrossular. The first ever identification of hydrogrossular garnet in the world was in 1943 by New Zealander Colin Hutton, from stones he found in Nelson. The term “grossular” comes from the Latin word for gooseberry, referring to the light-green colour of some hydrogrossular garnets. However, other minerals get mixed in, and white and brown are two other common colours. The browns especially usually have a very waxy feel when found. Milestone #15 has been tumble-polished so it now lacks that waxy character. See here for information on hydrogrossular garnets from TumbleStone2.

One of the larger stones, Milestone #16 was picked up by me because it reminded me of the appearance of marble. Its cloudy nature and its thin veins are reminiscent of marble stone. It is probably most likely a form of quartz, with a nice white colour on one side, a creamier hue on the other. This Post describes this type of stone and its variations.

Milestone #17 is a kind of banded argillite, and it may have a trace fossil at the top of its “other” side (see below). Argillite is a hardened, slightly recrystalised, mudstone, mainly grey through to black in colour but it can also be green and red (arising from the presence of iron). Green is the most common colour for argillite on Gemstone Beach, with some stones having trace fossil burrows and trails in them. They often polish very well. A thesis always contains different layers, which actually guide the writing – the chapters provide the most basic layer, and each chapter has an opening and a concluding layer. In between are layers which provide information arranged within the line of argument of the chapter.

Milestone #18 is a light-coloured stone with many fine silica veins running through it. It is probably a quartzite.  Quartzite is  a very hard durable metamorphic rock composed almost entirely of quartz. It forms when a quartz-rich sandstone is altered by the heat, pressure, and chemical activity of metamorphism. These conditions recrystallize the sand grains and the silica cement that binds them together. The result is a network of interlocking quartz grains of incredible strength. Impurities in quartzite can cause it to be yellow, orange, brown, green, or blue. Often it tumble-polishes very well. Milestone #18 is one of the medium-sized stones of the 36 I am giving to Lynley.

A smaller stone is Milestone #19, coloured purple and pink. When held up to the sunlight, tiny sparkles appear, probably the light reflecting off very small crystals of quartz. This helps to contribute to its delicate character, along with the fine strands of red within the pink. A good thesis pays attention to details, getting them right and getting them in order.

It is difficult to state with certainty what kind of stone is Milestone #20. It could be a brecciated stone, like Milestone #11. Or it could be a porphyry, a stone of volcanic origin, with crystals within it which have grown as the hot liquid rock cooled. However, many porhyries don’t have crystals as clearly defined as in this stone. Some amygdaloidal stones also look similar, where tiny holes in a volcanic rock has been infilled with minerals precipitating out of water which has flowed through it. (This variety of stones on Gemstone Beach is shown towards the end of this Post). My guess is that Milestone #20 is a porphyry, but I remain uncertain. It is not always easy to identify a stone found on the beach, even after extensive research.

Milestone #21 is a thin stone, almost boomerang shape. It is one of those stones that looks much better in person than in the photos, as the photos reveal tiny holes on its the surface. In person, the shapes within it are clearer and much more interesting.

Finally, Milestone #22 is probably a quartzite, like Milestone #18. Its mottled character does a much better job (compared to Milestone #21) of disguising its polishing imperfections in the close-up photos. There is an interesting complexity there, just like a good doctoral thesis!

Part Three in this Series looks at the remaining 14 milestones, all from Slope Point.