I’m not convinced those rocks in China really look like that in real life. I’m wondering about filtering being used etc. Here’s a youtube vid. They’re still pretty and they are colourful and maybe on a really bright sunny day they would take on even more colour but they don’t look like a Van Gogh painting
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I suspect some tweaking of saturation and contrast, but it’s also worth noting that the more muted photos and footage looked arid and dusty, whereas many of the more vivid ones had greenery in them - maybe the formations are naturally more colourful when it has been raining.
I spent a day at Koh Mook on that trip, lovely place; check this video I made there.
Although I have to say the the nearby island of Koh Lao Liang was the highlight for that trip.
The beach at Sivilai is my current screen saver! But we only walked to that beach a couple of times. We stayed at Charlie beach, for about 3wks, first at Hatfarang Resort, then at Sawadee bungalows, right on the beach. What a beautiful spot it was. We intended to continue on to Ko Lipe but decided to stay longer, because it was just so lovely! You gotta love an island without cars! Loved the all the wildlife (possibly not so much the howler monkeys!), plus bees as big as my fist and flowers the size of my head!
Three weeks, picture me envious.
I didn’t have the time to do much more than walking up and down the beach the first day and taking a boat to the Emerald Cave, I took this photo there which now that I look at it it shows some rocks with the same liver red/brown colour as my rock, but not the other colours or the banding.
I suppose that means this type of rock formed within the larger limestone formation?
I see similar ‘styled’ rocks occasionally when walking around South/Central Oklahoma areas, fwiw. Not as well delineated, but of differing compositions in the layers, along with random inclusions in the chunk I pick up to look at. May not be the exact same type of rock/minerals pictured, but its not odd to find such things around lakeshores here, etc, where ground is mainly made of old sedimented stuffs and has been eroded over time to expose the older/deeper layers. Just adding to all the above…
Wow, again. I’m bookmarking both videos and the fabulous view of the Emerald cave! They are spectacular truly.
I hadn’t considered using drones in this fashion, it’s awesome. Finally gave me a view of what was up the sides and tops of the karsks, very cool indeed!
I’d been to the Emeraid cave a decade earlier when the water was much lower. This time we went very late in the day and were only a handful of people, which was lovely. But we didn’t have any life vests, that would have been a very nice touch!
When you went to Ko Kradan did you, by any chance, see the ridgebacks? Because I was amazed, and taken aback by them. I’ve been in Thailand many times but never seen such a dog before.
At the most basic, I’m pretty sure you’d call the rock a quartzite which is a low-grade metamorphosed sandstone. The glassy luster you can see well in pic #3 combined with the sandy texture is very diagnostic of that. If you looked at it closely with a hand lens, you would probably see the individual grains starting to merge together.
The coloration, banding, and what it looks like are maybe some duller chunks could all just be weathering. It could also be something like a metamorphosed breccia, where the duller colored chunks were clasts of different material sitting in the sandy matrix. Sometimes you get something like that in fault gouge, where the movement of the fault breaks off big chunks of rock and sand or silica-rich fluids fill the space between them. The red coloration could even be early stages of jasperization, which is common in fault gouges, although if it were actually jasper you wouldn’t really see any sandy texture.
Actually we didn’t get to go to Koh Kradan, my GF booked a couple nights there but on the wrong month… so in theory we could go there at the end of this month (cancellations were not allowed, so it’s paid for), but I have work to do at that time so she may end up going with a friend instead.
Actually the glassy luster is water
I wanted the colours to stand up more, dry the rock is matte all over.
However I was thinking along the same lines, that it may be a type of sandstone not quite “baked” enough to fully crystallize, because it does look a lot like mookaite, but after trying to sand it I think it’s too porous to be polished.
I’ve been meaning to learn more about geology, to be able to pick up a rock and read it’s history and that of the surrounding landscape, it’s fascinating.
And that is one reason why some photos from the China formation look so colorful, they get that look after it rains. Once the normal dry conditions return then the slightly dull look returns.
You can see it in this article that does clarify that the best time to visit is just after it rains:
There’s no way that’s chalcedony, which is by definition cryptocrystalline.
It looks like a sandstone with surface mineral staining from weathering - possibly just dehydration or rehydration of iron oxides and some manganese, the colours fit.
But having said that, it’s actually fairly hard to tell a sandstone from a sandy limestone in a hand specimen without an acid test. Are you prepared to piss on the rock and see if it effervesces ?*
*
Oh man… that should teach me to read the footnotes.
No, seriously, what is it that I should do and look for? (with the vinegar and lemon juice) Leave the stone submerged, rub it or use some drops to see the reaction?
Pour some acid on (just a few drops will do) so that it wets the fresh (yellow) surface- if there’s fizzing, you have a limestone. If not, you don’t. Geologists usually carry dilute HCl bottles in the field, but if you absolutely must know right now, you use what’s available.
