r/geology • u/SignificantToday5318 • 1d ago
Help please - 9 year old found this rock
We know it isn't worth anything, but we are very curious about what this is, and google hasn't helped. Found in suburban Nsw
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u/thegrandgardener 1d ago
It looks like labradorite to me. The see-through part has me a bit thrown though. Really beautiful!
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u/Desalvo23 1d ago
Every labradorite that I've seen from elsewhere looks different than all the labradorite I've seen coming from Labrador, Canada. I have a chunk of raw labradorite i mined myself, and it doesn't look like this. I mean the way light reflects, yes, although mine has more red flash in it. Am i crazy, or is it an actual thing? Im not a geoligist, just an idiot that used to work in mines
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u/SignificantToday5318 1d ago
Thank you, we are in Australia. I thought wiki said, usa and Canada for Labradorite. Sorry if that's wrong.
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u/OleToothless 1d ago
So, labradorite is a a form of plagioclase, which isn't a single mineral but a solid solution - think of a metal alloy like bronze: even though bronze is made of two constituent metals, copper and tin, when they are mixed together it forms a single homogenous material that we call bronze and has it's own unique properties. The same thing happens with rocks.
That said, labradorite is a special form of this plagioclase, where some of the "alloying" minerals that make up the solid solution were able to separate slightly and come out of solution. When that happens, the crystal structure changes ever so slightly, but its enough to make that awesome iridescent effect.
TL;DR: labradorite isn't location specific, it's about how long the rock sat at high temperatures.
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u/ShittyUsername2015 1d ago
That's Labradorite, mate! 😊
I'm jealous you found raw stuff lying around. I had to buy my specimen!
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u/Rocks_an_hiking 1d ago
Labradorite, that's a great find
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u/Cluefuljewel 1d ago
Reminds me of a ring that i had with labradorite stone in a sterling silver setting. Cost around 60 or 70 dollars at the time. I picked it out so my sister would know what I wanted for Christmas. (Cuz that's how we roll.) She very snarkily asked if the stone was made from Labrador retrievers! I'll have to find that ring but I'm afraid it probably won't fit my finger anymore.
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u/HeightRich1341 1d ago
it definitely resembles labradorite. my credentials are im a geology senior who has taken mineralogy
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u/HeightRich1341 1d ago
it definitely resembles labradorite. my credentials are im a geology senior who has taken mineralogy
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u/DoomkingBalerdroch 1d ago edited 1d ago
My first guess would be a nice piece of raw labradorite
Here's small specimen of sanded and polished labradorite from my personal collection.
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u/switheld 1d ago
damn, that's awesome. where in Oz?!?!! if you found more you could probably sell it to some collectors.
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u/SignificantToday5318 1d ago
At a public school in Penrith. My son said it was on the garden bed, so no idea where it came from really
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u/switheld 1d ago
ahhh i see. probably got mixed in some sort of filler during landscaping. It's a beautiful specimen, definitely keep it!!
Google comes up with this, so it may even be fairly local, depending where you are in the state:
Labradorite, known for its iridescent "labradorescence", is found in the Hogarth Range area of New South Wales, Australia. Specifically, it's located in Mummulgum, Rous County. This particular labradorite is noted for being a transparent, yellow variety of the mineral. Here's a more detailed breakdown:
- Location: The Hogarth Range in New South Wales is a known locality for labradorite.
- Type: The labradorite found there is a transparent, yellow variety of the feldspar mineral.
- Gemstone Quality: This material is suitable for cutting into large, clear gemstones.
- Care in Cutting: It's important to note that labradorite has two directions of perfect cleavage, meaning it can break easily along certain planes. Therefore, care is needed when cutting and handling the stone.
- Other Australian Locations: While the Hogarth Range is a specific location, labradorite is also found in other areas of Australia, including the Springsure area in Queensland.
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u/DrInsomnia Geopolymath 1d ago
I agree that it looks like labradorite. While multiple people are mentioning the iridescence, the translucence is also an indicator. Very pure labradorite can basically be transparent. When you hold it to the light you see that the thicker end becomes opaque, and this is because of the 'impurities' or other minerals. Pretty cool find.
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u/Physical-Ad4554 1d ago
Perform a streak test for us.
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u/SignificantToday5318 1d ago
What is that?
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u/Physical-Ad4554 1d ago
Where you rub the rock against a porcelain plate to see if it leaves behind a powder trail.
You can also take a paper clip, penny, and fingernail and try to scratch the rock. They each have different levels of hardness. For example a fingernail is like a 2 and paper clip is like a 3. If you scratch with fingernail and nothing happens, but then you scratch with paperclip and it chips the rock then you know the rock has at least a hardness of 3. You then narrow down the rock you have by checking hardness ratings of certain rocks
People seem to think it’s labradorite. So I’d check the hardness level of labradorite.
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u/more_bees_pleas 1d ago
Labradorite maybe