Birdlings Flat III: Selection of Online Sources

BEACH FROM THE AIR – YouTube clip, Birdlings Flat and Halswell Quarry – the first 60 seconds of this short clip contains some aerial drone footage of Birdlings Flat, October 2017

LANDSCAPE DESCRIPTION – “Banks Peninsula Landscape Study”, for Christchurch City Council 2007, pages 194 to 197 are on Kaitorete Spit/Birdlings Flat

HISTORY – Wikipedia entry on “Birdling’s Flat”

TV PROGRAMME – Canterbury Television programme “Love Thy Neighbours” (August 1999) about some trouble between neighbours at Birdlings Fat, containing some good footage of the beach and village as well as some interesting historical material about the village (16 minutes 30 seconds long YouTube clip)

RADIO PROGRAMME – Country Life, “Down at the Beach”, 14 August 2014 Radio NZ Programme, interviews with 5 Birdlings Flat residents 

A BEACH RICH IN GEMSTONES – Te Ara, The Online Encyclopedia of New Zealand, brief entry “Looking for Gemstones, Birdlings Flat”

GEOMORPHOLOGICAL DEVELOPMENT – “Significant Coastal Lagoon Systems in the South Island New Zealand” by R.M. Kirk and G.A. Lauder, 2000, Department of Conservation, see pages 18-24 on “Waihora Lake Ellesmere” which also refers to Kaitorete Spit and Birdlings Flat

AGATES – Craig McGregor’s page on “Birdlings Flat Agates” from his website “Craigs Gems”

PHOTOS OF A VISIT – Licorice Allsorts, a blog by New Zealander Angela Hill, excellent set of photos taken on a visit to Birdlings Flat in May 2014

HISTORICAL SCIENTIFIC ARTICLE – “The Lake Ellesmere Spit with Map, Sections and Photographs” by R. Speight, in Transactions and Proceedings of the Royal Society of New Zealand, 1930

MOVIE CLIP OF NORTH END WAVES – YouTube clip, “Birdlings Flat North End Cliffs”, October 2012

ANOTHER MOVIE CLIP OF STORMY WAVES – YouTube clip, “Agate fossicking at Birdlings Flat with Doug”, showing some wild waves, Feb 2014 

PHOTOS OF GEMSTONES – Gemstones by Jocelyn Thornton, 1985, see page 33, “Beach pebbles – Birdlings Flat”

STONES – Country Chic Crafts New Zealand, a blog by Janette Ritchie from Springston, Canterbury, post on “New Zealand Gemstones” with a number of photos of Birdlings Flat stones, including agates and petrified wood

PHOTOS AND DESCRIPTION – Adrienne Rewi Online, a blog, post “Back to Birdlings”, November 2009 

Where Agates Can be Found in New Zealand

NOTE: 3 July 2019 – The mineralworld website referred below is no longer available currently on the internet. I have therefore included in square brackets below access to this material via the Internet Archive, as it existed in 2016-2017.

Mineralworld [see archiveis a website developed by Klaus Schäfer, [see archive], a German gemstone expert and jewellery-designer, who has done a lot of research and writing about gemstones, especially agates and jasper. He refers to his site as an “agate-almanac” – it is all about agates. An agate can be described technically as a translucent cryptocrystalline variety of quartz, a variegated chalcedony, characterised by colours in alternating stripes or bands, in irregular clouds, or in moss-like forms. Agates may have a wide variety of colour patterns and banding, with the many distinctive styles and patterns virtually making each agate unique. 

There are many pages on Klaus Schäfer’s website about agates worldwide, with a multitude of excellent and beautiful photos from a wide range of collections. Some of the information and articles are in German but there is much English material there as well.

Part of the website is called “Agates Worldwide” and has detailed descriptions of thousands of places where agates can be found. One page is the Index to the New Zealand material [see archive] where 28 locations are listed (such as Birdlings Flat, Hinds River, Nimmo’s Swamp, and Ward’s Beach). Click on a location and you are taken to a page with a description of the location and the agates that have been found there (usually written by NZ experts), illustrated with exquisite agate photos [NOTE: The Internet Archive very unfortunately did not archive these photos, but some agate photos can be found elsewhere on the archived site – click here for examples], four of which are below. The localities of origin of the agates in these photos are, from left to right: Nimmo’s Swamp, near Moeraki in Otago; Rangiatea Station near Mt Somers, Canterbury – this photo is by Malcolm Luxton who has recently published a book on “Agates of New Zealand” (see my comments on Luxton’s book in the section on Stone 11 in “Twelve Stones, Part Four“); Whitecliffs clay pit in Canterbury; and Gawler Downs Station near Mt Somers, Canterbury.

These agates were large enough to slice through so that their banding and internal patterns are shown to best effect. If agates are too small for this, they can be tumble polished like other small stones.

Regarding agates on TumbleStone, see also the following Posts: A) My Visit to Birdlings Flat, Day 2: Gemstone and Fossil Museum; B) Another Visit to Birdlings Flat, Late June 2016 – Part Three: Seven Types of Stones Collected; C) Polishing Agates from Birdlings Flat: Stage One; D) Stone #11 in Twelve Stones, Part Four; E) Milestone #6 in Nine Milestones at Journey’s End; and F) The May page in TumbleStone Calendar 2019 – February, March, April and May.

Seven Misleading Impressions from a Video Clip on Stone Tumbling

There are a number of video clips on YouTube about tumble polishing stones. This one, “The art of stone tumbling and polishing”, two minutes long, while it includes some good advice and shows the main steps involved, also conveys some misleading impressions:

1) This guy does it one-handed – you actually need both hands to do it well! (So when you make a video of it, it’s a good idea to get someone else to film you doing the demonstration.)

2) The number of stones he puts in the barrel, and the amount of water poured into it, is probably too much – most guides say fill the barrel about 2/3 to 3/4 full.

3) It’s not a good idea to let silicon carbide grit blow about in the breeze. It’s tiny and hard and sharp and you don’t want it to get into other stuff. It can do damage to a washing machine if it gets onto your clothes which are then washed.

4) He puts about one tablespoon of grit into what looks like a standard 3 pound barrel – there are different views about how much grit to use – a reasonably standard view is that you should use four tablespoons for this size barrel, some say half that, others say weigh the stones and put in a certain amount per pound of stones, and so on. You need to do your own research on this and maybe experiment with the amount.

5) “Secure lid on drum” – excellent advice, but this is not well demonstrated visually, given the one-handed approach. An insecure barrel lid is asking for disaster and the need for a clean-up.

6) “Pour off waste” after tumbling for seven days – yes, but make sure the waste does not end up down the drain where it is likely to accumulate in plumbing s-bends due to its weight and then set like concrete due to its composition! This is deemed by all leading instructors to be the most important piece of advice about tumble polishing stones.

7) “Tumble and wash each grit as before” – though sometimes you need only 3-5 days with the stage with the finest grit or a pre-polish powder, and the last stage involves a polish like tin oxide or cerium oxide.

It’s actually a great little video clip and gives me the opportunity to raise these points, all of which I am sure are well-known and appreciated by the video-maker. 

 

 

 

Sources of Detailed Instructions for Tumble Polishing Stones

The following are a number of sources I have found useful for the beginning (and also for the not-so-novice) rock tumbler. They share a number of things in common but also often have their own unique ideas or pieces of advice. (I will add to this List as I become aware of more sources).

1) RockTumbler.com “Rock Tumbler Instructions” – A reasonably detailed set of illustrated instructions. This site is based in USA and is the commercial site of a rock tumbler gone into business. It is noted that the owners of this site “publish what we believe is the largest library on the web of articles, videos and blog posts about tumbled stones and rock tumbling”. It is a mine of information – like stumbling upon a whole beach of colourful and already-rounded stones.

2) Alan Silverstein’s site “Collected Information on Rock Tumbling” – Sections on “Quick Start (Rotary Tumbling)” (updated 2008) and “More Detailed Advice on Rotary Tumbling” (updated 2011) – A no-frills but very informative set of instructions and advice. Alan is a software engineer from Colorado, USA.

3) Steve Hart’s book, “Modern Rock Tumbling” (first published 2008) – This whole book is full of useful information and advice on rock tumbling. The middle part of Chapter three is on “Understanding the 4-Stage Rock Tumbling Process”. Available from Steve himself and from all good online book sellers for about US$25.

4) “Professional Gemstone Tumbling” by Lortone (2011) – This is the 21-page booklet that came with my Lortone tumbler when I bought it. It is a set of basic reasonably-sound instructions, a very good starting point. I have not come across a copy of this online anywhere. Note that it is different from the “Rotary Tumbler Instructions and Parts List” that also came with the tumbler and is available online on Lortone’s website.

5) Lortone’s Instruction Videos – These consist of “How to fill a Lortone barrel” and three videos of how to change a drive belt on different Lortone tumblers. 

6) “Rotary Tumbling Guide” from Aussie Lapidary Forum – A more cryptic and informal set of instructions and advice but valuable in how the author shares their rock tumbling experiences and experiments. 

7) YouTube series on Rock Tumbling – Constructed by a US tumble polisher who uses his tumbler a handful of times a year, this series of six videos shows how he goes through the four stages of rock tumbling, using what looks like a 4lb barrel. The fifth video shows the resulting polished stones and the sixth video discusses what he does with his stones (he’s not into jewellery making). [Added 5 July 2019]

“Rock-collecting sites in New Zealand” – An Online Map

In Te Ara, the online New Zealand Encyclopedia, is a map of beaches in New Zealand where you can find agates and other interesting stones.  This is a very selective map and does not include, for example, Riverton at the bottom of the South Island, one of the best places for semi-precious stones. 

sites

“Gemstones” by Jocelyn Thornton (1985)

“Although New Zealand lacks the commonly accepted ‘precious gems’ (diamond, ruby, sapphire, emerald), many local stones deserve our recognition” (from the Introduction to “Gemstones”).

This booklet, originally published in 1985 in the Mobil New Zealand Nature Series, is long out-of-print but now available online as a pdf file. It is 36 pages long and a great source of information on the range of precious and semi-precious gemstones to be found in New Zealand – from greenstone to agate to jasper to petrified wood, and many more. It contains some great photos of the many different types of stones, supplemented with notes on where these specimens have been found (see below for the entry on “Carnelian”). Reference is often made to places such as Birdlings Flat, Rangitata River,  Orepuki, Kakanui, Mt Somers, the Coromandel Peninsula, and Takaka.

Joyce Thornton also 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, she received the NZ Order of Merit for services to Earth Sciences.