Category: Petrified wood

March 2026 Stone Collecting Trip – Part 14, Starting the Trip Back Home, A Fossick on Seadown Beach, Kakanui, Sunday 29 March

I reached Seadown Beach, just north of Kakanui, at 2pm this afternoon after a long drive from the south coast of Southland. It was raining during the first hour or two of the drive but scattered showers then dominated. At Seadown Beach, the tide was high but there were a lot of stones high up the beach, wet from the waves or from recent rain. This was especially the case among the rocks at the south end of the beach, where the stones have been piled higher than I have seen before.

Seadown Beach, Kakanui.
Looking north along Seadown Beach.
There were good pickings at the south end of the beach.

The sea must have recently been turning the stones over and churning them up because I had a very productive hour-long fossick. I found an amazing range of quartzites but a number of other very colourful and patterned stones as well, plus a piece of petrified wood.

This is the petrified wood, a relatively rare find for me on Seadown Beach:

Petrified wood.
Other side of petrified wood.

There are links to other specimens of petrified wood I have found on this beach here.

I think this next stone is what is known locally as limonite prase:

One side of this stone looks like plain quartz but the other side is far from plain:

The plain side.
The more interesting side.

A colourful orange stone with different patterns on different sides:

Another orange find, this one with some brecciation (tiny fragmentation):

These are seven of the quartzites I collected, quite a diverse lot:

I kept my eye open for the brown stones that sometimes contain tiny bryozoan fossils – this is the best candidate but I can’t clearly see such fossils in it:

And finally, an interesting mix of colours:

I return to Seadown Beach tomorrow. An Index to this Series is here.

Eight Recent Gemstone Beach Finds Polished, Including a Small White Orbicular Jasper and a Piece of Petrified Wood

Most of the stones I collect are already smooth and you can see the details in them very well when they are wet. However, when they are dry, they tend to become quite dull. So tumble polishing gives them a permanent wet look, as well as removing some of their rough bits, if they have any. I recently finished tumble polishing some of my finds from my two most recent trips to the bottom of the South Island, in September 2024 and March 2025. This Post features eight from Gemstone Beach. Note that where there are “before” and “after” photos, they were taken with a different camera and I’m still getting used to the new one.

The first featured stone is a small white orbicular jasper, the only one like this I have ever found. I picked it up on the last of my Gemstone Beach fossick earlier this year, on Friday 28 March, and the Post for that day has some information on orbicular jaspers. The first set of photos below is of the stone when found:

Small orbicular jasper with tiny white orbs.
Other side of stone.

I was reluctant to tumble it too much as it is small, two centimetres at its widest. So it underwent one 400 grit stage before going straight into polish. As a result, it’s not as smooth as it could be. However, by polishing it, its details are now permanently on show, otherwise you would need to wet the stone every time you wanted to see those details. The first side of the polished stone:

Side A.

The other side of the polished stone:

Side B.

I found a piece of petrified wood on Gemstone Beach on Wednesday 25 September 2024, a reasonably rare find these days. The stone when found:

Petrified wood, Gemstone Beach.
Other side of the petrified wood.

The following photos are of the tumble polished wood, though not strictly comparable as the first three below are of a different side to the first three above, and the second lot of three below had to be rotated to show the correct comparable orientation of the stone:

Tumble polished petrified wood.
Other side of tumble polished petrified wood.

The most gorgeous find I came across on Gemstone Beach on Wednesday 19 March 2025 was a tiny, one centimetre long, hematite poppy jasper, the size of my small fingernail. This is what it looked like when found:

Tiny jasper.
Another side of tiny jasper.

After tumble polishing:

Tiny polished hematite poppy jasper.

Another very small stone (two centimetres long) that I recently polished. I can’t find it in my fossicking Posts so don’t know when I found it on Gemstone Beach. I’m also not sure of its identification but was attracted by the lattice-like pattern on it:

One of the trace fossil argillite stones I have polished. Such stones don’t really take a polish but the tumbling clarifies the traces nicely:

You can read more about these trace fossils in “Southern Sojourn 2023(18): The Tattooed Rock, The Trace Fossils… Revisiting Gemstone Beach’s Trace Fossil Stones, February 2023”.

I like the range of colours in the next small stone – it is two and a half centimetres long:

Small polished Gemstone Beach find.

The seventh stone in this Post is a good example of the kind of details I like in a stone, revealed by the close-up photos. There are tiny colourful veins and tiny patches of brecciation – here is the polished stone:

Polished Gemstone Beach find.
Other side of stone.

I found this seventh stone on Gemstone Beach on 27 March 2025 and the first side looked like this at the time:

Unpolished stone.

I chose the last stone to feature in this current Post because it has hematite in it, a mineral I have an interest in. Holding this stone on a certain angle to the light shows up small patches of the distinctive metallic grey of hematite, even though the photos don’t show it:

The tumble polishing continues…

TS2 – SLOPE POINT: THE STONES

Black Point Beach, Slope Point.
Stones, Black Point Beach.
Bach Beach, Slope Point.
Stones, Bach Beach.

Many of the stones on Slope Point beaches are different from those I have found on other South Island beaches. There is a preponderance of volcanic stones, especially rhyolites (see Thornton’s “Gemstones”, page 35 here) (see photos below). Many of the rhyolites are colourful and contain interesting patterns, such as flow-bands and orbs. One kind of rhyolite is spherulitic, also known as “chrysanthemum rhyolite”. “Flower garden” is the local name for a rhyolite with “white and grey circles and centres” (Thornton, page 35 here) (second row below, far right).

Flow-banded rhyolite.
Flow-banded rhyolite.
Rhyolite.
Rhyolite.
Chrysanthemum rhyolite. Found by Oliver Simpson.
Chrysanthemum rhyolite.
Chrysanthemum rhyolite.
“Flower garden” rhyolite.

Rhyolite has a very high silica content and is the volcanic equivalent of granite. It is formed from magma that is extruded from a volcanic vent to cool quickly on the surface rather than slowly below ground. Generally fine-grained in texture, rhyolite may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matrix. Depending on the nature of its emergence, rhyolite can also take the form of obsidian and pumice. According to John Farndon’s (2015) “Illustrated Guide to Rocks & Minerals”, spherulitic rhyolite originates in “gas pockets of volatile vapours” which develop into “balls of radiating needle-like crystals of quartz and feldspar” (page 64) . Useful online sources on rhyolite are Geology.com and Alex Strekeisen. Mindat has photos of a variety of rhyolites, including spherulitic ones.

The petrified wood found on Slope Point beaches is often black but it can also be brown or grey (see photos below, top row). It is likely to have been caused by burial from volcanic-induced land slides. Fossilised tree fern stems (punga) can also be found here (see below, bottom row), though they are not common. Some of the specimens below were found by Oliver Simpson and I tumble polished them for him. As Thornton puts it in her “Gemstones” booklet (1985), “Wood can be turned to stone when it is buried in waterlogged sediments carrying dissolved minerals which soak into the wood and replace the organic material or seal it from decay” (page 21). Interesting online material about petrified wood can be found at Rockseeker.com and Wikipedia.

Black Slope Point petrified wood.
Slope Point petrified wood.
Slope Point petrified wood.
Fossil tree fern stem, Slope Point. Faint shapes. Found by Oliver Simpson.
Fossil tree fern stem, Slope Point.
Fossil tree fern stem, Slope Point. Found by Oliver Simpson.
Fossil forest floor, Slope Point.

Another Slope Point stone is called fossil forest floor – Thornton refers to it as material preserved in silica: “stems, roots, leaves and so on” (see page 24 here). One specimen is shown immediately above, far right of second row.

Oliver once found a fossil coral stone at Slope Point (photo below, top left), maybe agatised (see this Post about a Gemstone Beach find for some information on fossil coral). Beach agates are rare on these beaches, though agate or chalcedony veins or infilled crevices can be seen in some stones. One unusual type of agate, a joon agate, can be found here but it too is rare. The final stone below, second row far right, is full of tiny unidentified fossils of some type.

Fossil coral from Slope Point. Found by Oliver Simpson.
Small beach agate, Slope Point.
Unusual Slope Point agate.
Agate veins and in-filled crevices can be found in Slope Point stones.
Slope Point stone with agate in tiny veins.
Agate in large petrified wood rock, Slope Point.
Maybe a joon agate, Slope Point.
Slope Point stone with unidentified tiny fossils.

There are a lot of breccia stones amongst my Slope Point finds. I have also found two poppy jaspers (one quite tiny) and one stone similar to Kakanui’s fossil bryozoa. A range of other more common stones occur at Slope Point as well, such as jasper, granite and quartzite.

Slope Point breccia stone.
Slope Point breccia stone.
Slope Point breccia with some rounded clasts.
Poppy jasper, Slope Point.
Slope Point stone similar to Kakanui bryozoan fossil stone.
Small Slope Point jasper.
Small granite stone, Slope Point.
Quartzite, Slope Point.

The following are the Posts on TumbleStone Blog significantly featuring these Slope Point stones:

Return to SLOPE POINT

HOME – FOSSICKING BEACHES – BEACH STONES – TUMBLE-POLISHING

Southern Sojourn 2023(50): An Orbicular Rhyolite and A Large Piece of Petrified Wood, A Return to Slope Point, Saturday 22 April

Post 50
Post 51 https://tumblestoneblog.wordpress.com/2023/04/24/southern-sojourn-202351-a-bunch-of-quirky-stones-from-gemstone-beach-te-waewae-bay-sunday-23-april/
Post 1
Post 2
Post 3

This morning I made my last visit for this Southern Sojourn to Slope Point (I’m heading home to Whanganui in a week’s time). I went to the same beach as featured in Post 30. The weather was wet for much of the time and so were all the stones on the beach – this made spotting the interesting ones a bit easier. Despite trying to be selective, I ended up collected 9.5 kilograms of small stones, about 130 stones in all. The best of all these was this gorgeous orbicular rhyolite:

Slope Point orbicular rhyolite.
Other side of stone.

My most interesting find today, however, was a large piece of petrified wood (26 cms long, 2.5 kilograms weight). On my way to the beach where I collected my pebbles, the fact that it was low tide meant that I could nose around some rocks in an area I haven’t been to before. At one point I stopped to check my backpack. Looking down, I saw this large piece of brown petrified wood. It was partly under another large stone but came free easily. While photographing it, I kept finding little areas of agate. Even though I won’t be able to tumble-polish it, I am very happy to have such a fine specimen.

One side of the large piece of petrified wood.
Other side of piece.

Three more of the small stones I found that had interesting detail:

Other side of stone.
Other side of stone.
Some agate in this stone.
A little druzy on this side of the stone.

Three light-coloured stones with intriguing detail:

Three more visually interesting Slope Point finds:

So it’s farewell to Slope Point for now. Until next time!

The stones on this Slope Point Beach today.
Halfway up the steep climb back to the car, backpack heavy.
The 130 small stones I collected today.

Post 51 features some “quirky” stones. The first Post in the “Southern Sojourn 2023” Series is here. The Index to the Series is here.

Twenty-Five Slope Point Stones Polished for Oliver, July 2022: Part 2, Stones 9 to 15 (Petrified Wood)

In Part 1, I introduced eight stones that I had tumble-polished for my fossicking buddy, Oliver Simpson, who lives near Slope Point in Southland. One of those was petrified wood, and this Post features seven more polished stones of this type. The most common colour for petrified wood in the area is black, but lighter varieties are also present. I will present the lighter stones first.

Stone 9.
Stone 11.
Stone 10.
Stone 12.
Stone 15.

Stone 9 is the largest of all the 25 stones. It is right at the upper boundary of what I feel I can tumble polish. I also did not want to reduce its size too much – reduction results in a smoother outcome – as Oliver was mainly interested in just clarifying the grain and veins. There is some brecciation apparent in the central vein.

Stone 9, Slope Point petrified wood.
Stone 9.
The other side of Stone 9.

Stone 10 has a light grey hue and a mottled bottom. It is also a decent size (for a tumble-polisher).

Top of Stone 10.
Stone 10.
One of the sides of Stone 10.
Another side of Stone 10.
Bottom of Stone 10.

Stones 11 and 12 are much smaller. Stone 11 has one face that displays its grain very nicely.

Stone 11.
Another face of Stone 11.
Stone 11.
Stone 12.
Stone 12.
Another side of Stone 12.

Stones 13 and 14 are darker in colour. Stone 13 was difficult to get a clear clear photo of because of its high polish. By contrast, Stone 14 did not take a good polish, maybe because the material is a little softer.

Stone 13.
Another side of Stone 13.
Stone 14.
Another side of Stone 14.

Finally, Stone 15 is very black. It is probably fossilised tree fern, given the shapes that can be discerned in it.

Stone 15, fossilised tree fern?
Stone 15.
The other side of Stone 15.

Part 3 in this Series features the remaining ten stones, which include a number of orbicular and brecciated ones.

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.
Petrified wood, Slope Point.
Petrified wood, 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”.

January 2022, Stone of the Day #17 – Another Kakanui Petrified Wood, and Woven Petrified Timelines

This piece of petrified wood was found on the same beach at Kakanui as Stone #6 and was polished in the same batch:

It is 5 cms long, 2 cms at its widest and only between 2 mms and 5 mms thick. It has a great colour, with the wood grain showing clearly, and it has polished very smoothly:

Other side of Stone #17.

The grain of petrified wood can vary significantly from piece to piece and from place to place, depending on the type of wood and the conditions of petrification. Mathew Vanner is a PhD candidate at the University of Otago who has conducted serious research into New Zealand’s petrified wood for a number of years. As a school boy, he had been introduced to fossil wood by Jack Geerlings of Winton. I met Jack on Gemstone Beach in 2019 and he invited me to visit him and see his extensive collection of stones and rocks, polished and rough. A few pieces of his petrified wood:

Jack Geerling holding some petrified wood (the unpolished side).
Petrified wood polished by Jack Geerling.
Petrified wood polished by Jack Geerling.
Petrified wood polished by Jack Geerling.
Part of Jack Geerling’s display of polished stones.
Part of Jack Geerling’s stores of unpolished rocks.

Some of Mathew’s microscopic slides of petrified wood have inspired weaver and artist Pam McKinlay to produce (during the Covid-19 national lockdown) a woven wall hanging that captures “forest timelines caught in stone”. Wood grain in stone is captured in the lines of the weaving. Pam McKinlay collaborates with other artists in community outreach and art+science education projects on the themes of climate change, sustainability and biodiversity. Her account of this project can be found on the Surface Design Association Blog here and a slightly more detailed report is here.

Source: http://www.surfacedesign.org/a-petrified-sampler-forest-timelines-caught-in-stone-by-pam-mckinlay/
Source: http://www.surfacedesign.org/a-petrified-sampler-forest-timelines-caught-in-stone-by-pam-mckinlay/
Source: http://www.surfacedesign.org/a-petrified-sampler-forest-timelines-caught-in-stone-by-pam-mckinlay/

The beach on which I found Stone #17 is just a couple of kilometres north of Kakanui village and about 12 kilometres south of Oamaru.

The beach near Kakanui on a fine day.
A photo of the beach on a cloudy day.
I scared this little crab while fossicking – a “petrified” crab?

The Index to the January 2022 Stone of the Day Series is here.

January 2022, Stone of the Day #10 – Light-Coloured Petrified Wood from Slope Point

Most of the petrified wood in the area of Slope Point, Southland, is dark coloured if not black. Occasionally I have come across a brown piece incorporating veins of some kind of silicate, maybe quartz or chalcedony (agate). This is maybe my favourite Slope Point stone so far (though it might also be one that Oliver Simpson found and gave to me):

This stone is 3.5 cms at its longest. It came out of the polishing barrel yesterday. I had earlier twice given it a 400 grit tumble as it has a number of cracks in it. I didn’t start with 220 grit as I wanted to have some control over its shaping, to make sure I didn’t make it too small while trying to minimise the size of the cracks. It was impossible to get rid of the cracks, but the stone is gorgeous.

The other side of Stone #10.
One of the ends of Stone #10.
One of the edges of Stone #10.

It spent 13 days in tin oxide tumble polish followed by three days in borax.

The following photos include examples of the more common black petrified wood from Slope Point. The first photo is of five stones tumbled in the same batch as Stone #10:

Five polished black petrified wood stones from Slope Point.
Polished black petrified wood stone from Slope Point.
Unpolished black petrified wood from Slope Point.
Unpolished black petrified wood from Slope Point.
The fossicking beaches at Slope Point are to the west of the tourist sign.
Slope Point beach stones.

More TumbleStone Blog photos of polished Slope Point stones, including black and brown petrified wood, can be found here.

Stone of the Day #11 is here. The Index to the January 2022 Stone of the Day Series is here.

January 2022, Stone of the Day #6 – Petrified Wood from a Kakanui Beach

I’m not sure when I found this stone at Kakanui, just south of Oamaru in North Otago. It is one of maybe eight to ten pieces of petrified wood I have found there over the last 18 months. It’s an unusual shape but has tumble-polished quite well. It feels very smooth on the two large sides though close-up photos have revealed some tiny rough patches.

The stone is 4 cms long by 2.5 cms at its widest and 1 cm deep. Photos of the other side and of the concave edge which seems to have escaped the full effects of tumbling, being a little rougher as a result :

This stone was tumble-polished in a 3lb barrel for 14 days in tin oxide tumble polish, followed by three days burnishing tumble in borax. The barrel contained Kakanui stones that had mainly had 14 days in 600 grit first. But I needed some more to fill the barrel to the two-thirds level. Stone #6 was one of nine added that had previously undergone only a 400 grit tumble. I took a photo of the nine so I could identify them later to see if there was much of a difference in their polishing (and I couldn’t detect any, though remember that I had previously decided that the nine were smooth enough to go directly to tumble polish). Note that this photo was taken inside, in a dim room – this accounts for the dark colour of Stone #6:

The nine stones previously tumbled only in 400 grit.
Stone #6 before going into tumble polish.

There were three other pieces of Kakanui petrified wood that were tumbled in the same 3lb barrel – the middle one failed to take any shine at all, despite having a pre-polish tumble in 600 grit (this happens with petrified wood from time to time):

Three other Kakanui petrified wood stones polished in the same barrel.
This one did not shine at all!

Finally, three other examples of Kakanui petrified wood, these ones having been found in June and September 2021, the photos taken on the day they were found on the beach:

Found June 2021.
Found June 2021.
Found September 2021.

Note: A good description of the process of wood petrification can be found in Jocelyn Thornton’s “Gemstones” booklet – see page 21 of the online version.

Stone of the Day #7 is here. The Index to the January 2022 Stone of the Day Series is here.

“K” is for “Kai Iwi Beach Stone” and “L” is for “Leithfield Beach Petrified Wood”

F is for Fossil Worm Cast
G is for Green Hydrogrossular
H is for Hematite Jasper
I is for Ichnogenus Protovirgularia
J is for (Picture) Jasper

The following are my Posts for “K” and “L” in the alphabetical series of a Facebook Group I belong to, “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Posts in this Series can be found here.

“K” is for “Kai Iwi Beach Stone” – This beach, about two kilometres from my home, is probably named after the Kai Iwi Stream that emerges here at the coast, a few kilometres north of Whanganui. Kai Iwi Beach is at the small town of Mowhanau, site of the Kai Iwi Beach Holiday Park run by Bruce Taylor (another Group member) and his wife. There are usually not a lot of stones on this beach but I have occasionally been collecting mainly iron-stained quartz to tumble-polish, discovering some nice-looking pebbles, like this one.

K is for Kai Iwi Beach Stone
https://www.google.co.nz/…/@-39.8853384…/data=!3m1!1e3
Kai Iwi Beach, looking north/north-west from near the stream mouth.
Kai Iwi Stream mouth, with pedestrian bridge. Often quite a few stones can be found downstream of the bridge.
Looking back at the pedestrian bridge.
Along the cliffs to the south.
Typical scattering of stones on the beach.
The cliffs to the south.

For more on the Kai Iwi Beach stones I have tumble-polished and more about the beach, see the previous TumbleStone Post here.

“L” is for “Leithfield Beach petrified wood”. I wrote in a post on this Facebook Group on 26 August 2020: “Yesterday I visited Leithfield Beach, just north of Christchurch, for the first time, mainly because at least one person had posted in this Group recently that he had found petrified wood there. I have found very few specimens of petrified wood in my fossicking career and have never been sure of its identification. So I walked Leithfield Beach for a couple of hours while rain showers came across. I was delighted to find five pieces of petrified wood that were obviously petrified wood because they actually looked like wood!”

L is for Leithfield Beach petrified wood
Photo of the piece on the beach when found, taken with my phone.

As Jocelyn Thornton wrote in “Gemstones”, wood can be turned to stone when it is buried in waterlogged sediments carrying dissolved minerals which soak into the wood and replace the organic material. The wood’s cell walls usually act as a “template” for the mineralisation, retaining the wood-like look.

Leithfield Beach, google maps. I park at the north end of the town when making a fossicking visit.
Looking south from the car park I use.
This old storm-water pipe was recently being dismantled. I like to walk down to that area.
Looking north from the car park.
The stones of Leithfield Beach.
Jocelyn Thornton’s introductory piece on petrified wood. The numbers refer to photos – see next pic.
The photo of specimens for Jocelyn Thornton’s introductory piece on petrified wood.

I have yet to repeat my fossicking success of that day in relation to petrified wood.

See here for the next Post in this Series, and here for the Series Index.