I wrote this Review for the November 2025 edition of “StoneSpeak”, the Newsletter of the Southland Geological and Lapidary Club. The following is a slightly fuller version. I previously did a brief Post on the same publication in TumbleStone Blog in April 2016. The Southland Club’s website is here and its Facebook Page is here.
Jocelyn Thornton’s booklet “Gemstones” was first published in 1985 by Reed Methuen in the Mobil New Zealand Nature Series. It was produced to be used in the field – it has slightly thicker pages than usual, a spiral binding, and it’s of a size to fit in a large pocket. It’s a guide for stone collectors, polishers and cutters to the kind of material that can be found mainly on beaches in New Zealand. Each section has photos of stones on one side, and a numbered key and description of stones on the other. It’s an invaluable resource for stone fossickers and lapidarists, and there is no comparable book around. I managed to buy a second-hand copy about ten years ago but it is now rare, and we are fortunate that it has been made available online.
Jocelyn Thornton was born in Wellington, initially working as a journalist after studying English literature at university (see Micromounters Hall of Fame). In the mid-1960s, she took up rock and mineral collecting as a hobby then returned to university in 1977 to study geology. For many years she has been honorary curator of the Alexander Mackay Geological Museum at Victoria University of Wellington (see photo below, left).
As well as “Gemstones”, she has written “The Field Guide to New Zealand Geology: An Introduction to Rocks, Minerals and Fossils”, also published in 1985 but revised and up-dated a couple of times since. This is a substantial publication, covering the country’s geology within a framework of geological eras but also New Zealand regions. Its photographs are taken from the road or the beach, showing formations accessible to the average traveller. It is aimed at the general public and beginners in geology.
In 2009, Thornton wrote the entry on “Gemstones” for Te Ara, the Online NZ Encyclopedia. This entry has some excellent photos of different types of stones, such as “Silicified Wood and Plant Material”, “Chert, Flint and Jasper”, and “Greywacke Pebbles with Quartz Veins”. In 2004, Jocelyn Thornton received the NZ Order of Merit for services to Earth Sciences.
To get back to Thornton’s “Gemstones” booklet: It used to be available on her husband’s website, but that disappeared in 2022. Soon after, it was posted on the information site of Tuatapere, a town in Western Southland. The site is called “On Natures Edge – Tuatapere” and its “What’s Here” section has a brief page on nearby Gemstone Beach which includes a link that brings up a pdf file of the booklet.
Thornton’s “Introduction” to her booklet is very good, covering the topics of gemstones, NZ’s stones, polishing and other lapidary techniques, access issues, and equipment for beach collecting. She acknowledges assistance from various local rock and mineral clubs. There are two main sections in the booklet: 25 pages on specific types of stones, with photos, and 7 pages on stones from different areas/beaches, again with photos.
A wide range of stones are covered, from greenstone to quartz to jasper to petrified wood. Thornton’s comments on them refer to their characteristics and where they can be found. The regional coverage in the second section is patchy (for example, Northland is not included), sometimes quite general (one page is dedicated to the East Coast from Hawke Bay to North Canterbury) and sometimes very specific (Birdlings Flat, Slope Point and Orepuki have their own pages). If you are interested in the likes of the stones from Orepuki (Gemstone Beach), don’t just look at the page on that location – also check out the pages on the kinds of stones to be found there, such as Garnet, Jasper and Quartz.
If you want to identify a stone and have only a vague idea of what it might be, Thornton’s “Gemstones” might be able to help you, if you slowly look through its pages. If you are visiting one of the beaches she covers, the booklet will alert you to the kinds of stones you will encounter. There is a lot of material in it and I often consult it. One of its limitations is the quality of the photographs. I often wish they were brighter or more detailed, but maybe that relates to the technology of the time and the need to keep expenses down. It also has no index, so if I’m looking for information on thulite, for instance, it’s difficult to work out if it’s in there – in fact, I don’t think it is. And that’s another limitation of the booklet, it doesn’t include all the significant stones to be found at different places. It’s selective in its coverage, maybe due to the stones that were available to Thornton to photograph. However, this doesn’t detract from its great usefulness to anyone interested in New Zealand’s stones. Like any good thing, you always wish for more.
The next Review in this Series is of the “Sandatlas” Website. An Index to this Series is here.
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