May 2022 – TumbleStone

“TumbleStoneTwo” Under Construction – A New Website Within A Blog

TumbleStone Blog, as viewed on a laptop.

A stony beach. Ward Beach.

4lb rotary stone polisher, manufactured by Lortone, USA.

Draft of a page in TumbleStoneTwo.

For the past few months, I have been trying to think of ways of presenting the information within TumbleStone Blog in a more systematic and accessible way. This was prompted by a number of questions that arose in my mind. For example: How easy is it for someone to find an introduction to Gemstone Beach on my blog? How would someone interested in a particular stone, like orbicular jasper, be able to find the Posts that refer to it? For a beginning tumble polisher, how would they be able to find useful information on my blog? There are some Posts that provide a good introduction to a topic, or a good overview of it, but they get buried in the chronological layering of Posts. Furthermore, the “Categories” tags for topics down the righthand side of the Blog don’t discriminate between introductory Posts and Posts that might simply include reference to the topic. Using the “Categories”, each Post so tagged is shown in its entirety and it can be daunting to read through them all. The “Search” function (just below the banner on the right, near the top of each Post) brings up all the Posts using that word, and in abbreviated form, so that can be an improvement. But the mobile phone version of the Blog does not show the Categories list or the Search function. And Google doesn’t always solve the problem either.

So, just recently, I decided to try to develop a website within the blog to overcome these problems and make my material more accessible and useful. A home page will be the key – it will provide links to three main sections, Fossicking Beaches, Beach Stones, and Tumble-Polishing. Links will then be made to different beaches that I know well, to beach stones I have some familiarity with, and to information about tumble polishing beach stones. All of this will reflect my own experiences, the range and limits of my knowledge and understanding, and my own preoccupations and biases. Lists of relevant TumbleStone Blog Posts will be compiled, along with the re-packaging of Blog information and the preparation of new material. All of this will take time – it is a project in progress, with newly constructed pages posted from time to time, interrupted by the distractions of fossicking trips, tumble polishing, and everyday life.

Glimpses of drafts of eight of the “TumbleStoneTwo” pages I have been working on are provided below. The first (see below, left) is the top part of the current draft of the home page, with the key function of the page being to provide links to the three main sections – Fossicking Beaches, Beach Stones, and Tumble-Polishing. The second (below, right) is part of the main page for “Fossicking Beaches”, with links envisaged at this stage to nine beaches (or areas) that I know well. These are, in alphabetical order, Birdlings Flat, Gemstone Beach, Kaikoura Coast, Kakanui, Leithfield Beach, Riverton/Aparima, Slope Point, Timaru, and Ward Beach.

Below (left) is the main page for Gemstone Beach. One of the links on that page will be to a page about Gemstone Beach in the context of the Te Waewae Bay coast (below, right).

One of the pages on Birdlings Flat will list Blog Posts on my fossicking experiences at that beach (below, left). It is intended that the main Beach Stones page (see below, right) will link to pages on types of stones that I have collected and polished, that I have found on the nine beaches mentioned earlier.

The first beach stone I have been working on for TumbleStoneTwo is hydrogrossular garnet:

I will probably post the Home Page sometime over the next few days and then add other pages progressively over time as they become available.

From Kakanui to Whanganui and back to Oamaru: Two and Twenty Stones

The beach near Kakanui where all these stones were found. Looking south.

Looking north along the Kakanui beach. The sand moves in and out periodically.

Kakanui beach stones.

Waves breaking on the rocks at the south end of the beach. at high tide

During a fossick on a beach near Kakanui (North Otago) on 6 March this year, I met Barb and Derek (see the end of the Post February-March 2022 Fossicking Trip: Stone of the Day #24, Kakanui Multi-Coloured Quartzite; for an introduction to the Kakanui beach, see this Post). They regularly walk this stretch of beach, picking up rubbish as well as an occasional stone. Barb had just found a small smooth gray quartz stone and I offered to tumble-polish it for her. Derek found a small beach agate while we were chatting – he gave it to me and I tumbled it in the same batch as Barb’s stone, which included a number of Kakanui stones.

Barb’s grey quartz stone., when found

Derek’s beach agate, when found.

After tumbling the stones in 400 grit for a couple of weeks, they spent 11 days in tumble polish (tin oxide) and five days in a burnishing borax tumble. I will put them in the mail tomorrow to Barb and Derek in Oamaru, along with 20 other small Kakanui stones.

Barb’s stone, polished.

Barb’s stone held up to the sun.

Barb’s stone with a torch behind it.

Derek’s beach agate, polished.

Other side of Derek’s beach agate.

Barb’s grey quartz stone has emerged very smooth from the process though some internal “cracks” are able to be seen. Derek’s beach agate has lost some of the interesting white weathering patterns on its surface, with only a small squiggle left on one side. The other 20 Kakanui stones were tumbled in the same batch, many of them being quartzites, some with tiny clear quartz crystals in them, as these three below have.

B = Barb’s stone. D = Derek’s stone. $2 coin for scale. The rest are the other 20 Kakaknui stones I sent them.

Stone 6 of the 20.

Other side of Stone 6.

Stone 9.

Other side of Stone 9.

Stone 16.

Other side of Stone 16.

Stones 1 to 5 are also likely to be quartzites (see photos below). As with many small stones when being tumble polished, decisions have to be made about how smooth to get them before the final polish. Sometimes, getting them completely smooth may may the stone very small. In order to retain their interesting patterns, some small holes or rough patches may end up remaining.

Stone 1.

Stone 2.

Stone 3.

Stone 4.

Stone 5.

The following five are also likely to be quartzites. The last of these, Stone 19, is a particularly unusual one for its colour and the number of clear crystals in it.

Stone 8.

Stone 10.

Stone 14.

Stone 17.

Stone 19.

Stone 12 (see below) is another quartzite while Stones 11, 13 and 15 are likely to be varieties of quartz, with Stone 15 having some interesting moss-like inclusions:

Stone 12.

Stone 11.

Stone 13.

Stone 15.

The three remaining stones are jaspers, which are often a challenge to polish:

Stone 7.

Stone 18.

Stone 20.

Anyone who spends time on beaches understands how much rubbish, especially plastics, can be found there. Anyone who picks it up to remove it from the beach is well worthy of our encouragement and support.

Using Bleach on Black Petrified Wood from Slope Point

On the beaches at Slope Point in the Catlins, Southland, New Zealand, petrified wood of various colours can be found. Perhaps most common is the black variety. Some of the black petrified wood shows some lighter-coloured grain within it but some does not. When wet, the black petrified wood often shows little or no grain – when dry, it becomes a little lighter in colour and may reveal some grain.

The largest piece of petrified wood I have collected from Slope Point – wet.

The same piece dry.

Black petrified wood from Slope Point.

Petrified wood, Slope Point.

Jocelyn Thornton, in her booklet “Gemstones”, has a page on “Beach Pebbles – Slope Point” (see photo below, left, paragraph labelled 1). In there, she states that collectors often place black petrified punga and other stones in household bleach overnight “after which the grain of wood…is revealed” (see page 35 of “Gemstones”). In the Birdlings Flat Gemstone and Fossil Museum, Vince Burke includes an example of Slope Point petrified wood “bleached to bring out the grain” (see photo below, middle). Having heard of this practice mentioned by a couple of other collectors, including Tracey Kidd (photo below, right), I decided to try it out.

Source: Page 35 of http://www.peterthornton.com/files/nzgemstones.pdf

Birdlings Flat Gemstone and Fossil Museum.

Tracey Kidd’s bleached and unbleached petrified wood from Conway River.

In a recent discussion in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”, a member mentioned that he had soaked a piece of black petrified wood “in straight bleach for a few weeks”. In a 2013 discussion in The Fossil Forum on the use of bleach, a UK contributor stated: “If the starting material is black or very dark in colour, it should bring up the grain but you’ll probably need to leave it soaking for about a month (in a non-metal container) and top up with fresh bleach every few days”. In the US-based Rock Tumbling Hobby Forum, one contributor from Oregon showed before and after photos of petrified sycamore which had been polished then soaked in bleach “for a few days” (see photos below, left and middle). On the same Forum, another showed the results of bleaching polished black petrified wood from Montana for three to four days (see photo below right). What emerges from the discussions on these forums is, in general, it seems that people can use bleach either before or after polishing, they often use full strength bleach, it affects only the outer layer of the stone, it is successful for only some types of petrified wood, and the same effect can be achieved by leaving the petrified wood in direct sunlight for a year or more.

Petrified Oregon sycamore, after polishing but before bleaching. Source: https://forum.rocktumblinghobby.com/thread/88041/bleached-sycamore

Same slab of petrified Oregon sycamore, after polishing and bleaching. Source: https://forum.rocktumblinghobby.com/thread/88041/bleached-sycamore

Two pieces of originally similar Montana petrified wood, the piece on the left having been bleached. Source: https://forum.rocktumblinghobby.com/thread/85292/bleaching-petrified-wood

I had not read these before I started my own experiment. However, Tracey Kidd had told me she had used a 50/50 dilution of bleach and had soaked her un-polished petrified wood in it for about 18 hours. I selected 12 pieces of black Slope Point petrified wood (unpolished) and decided to try them in a solution of 1/3 bleach and 2/3 water for two days.

Placing the stones in the diluted bleach solution.

After two days.

The nine pieces of petrified wood BEFORE.

The nine pieces of petrified wood AFTER.

The results were mixed, probably dependent on the nature of the petrified wood, how “open” the grain is. This is demonstrated by the largest piece, #1 (11 cms long). [Note: Taking photos of un-polished black petrified wood poses a number of challenges, with the angle to the light giving different results – many of my pieces below looked blacker before bleaching than represented in the photos.] On one side, the smoother side with less grain being revealed, has retained more black than the other side. This is the side that ended up blacker, with one line of grain along it:

#1, side a, before bleach.

Detail of #1, side a, before bleach.

#1, side a, after bleach.

Detail of #1, side a, after bleach.

This is the side that ended up lighter, with more grain apparent on it:

#1, side b, before bleach.

Detail of #1, side b, before bleach.

#1, side b, after bleach.

Detail of #1, side b, after bleach.

One side of #9 (side a) remained the blackest after the bleach:

#9, side a, before.

#9, side a, after.

#9, side b, before.

#9, side b, after.

One side of piece #6 showed some brown patches after bleaching:

#6, side a, before.

#6, side a, after.

#6, side b, before.

#6, side b, after.

Piece #12 is something like fossil tree fern and I hoped the bleach would bring out its patterns more clearly. There was a small improvement:

#12, side a, before.

#12, side a, after.

#12, side b, before.

#12, side b, after.

Three of the other stones, #7, #8 and #11:

#7, side a, before.

#7, side a, after.

#7, side b, before.

#7, side b, after.

#8, side a, before.

#8, side a, after.

#8, side b, before.

#8, side b, after.

#11, side a, before.

#11, side a, after.

#11, side b, before.

#11, side b, after.

In some cases, the bleaching these stones has resulted in a grey surface that is less interesting than the original black. In other cases, wood grain patterns have been made clearer and brown patches revealed. Sometime in the future, I will experiment with polished petrified wood and see what happens.

TumbleStone Posts with examples of petrified wood stones from Slope Point: “Twenty-Four Slope Point Stones Polished for Oliver: Part 1, Stones 1 to 10”, “Twenty-Four Slope Point Stones Polished for Oliver: Part 2, Stones 11 to 24”, “Another South Island Fossicking Trip, February/ March 2021 – Days 15 and 16 (Slope Point, Gemstone Beach)” and “January 2022, Stone of the Day #10 – Light-Coloured Petrified Wood from Slope Point”.