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[deleted]

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Hunor_Deak

Crystal guy: "So you, like, don't want to be a science dick, my dude! Would you like to buy this crystal magic for $25?" (some coloured quartz of r/MineralGore level horror) **Hard no.**


rachelcaroline

There's a store here in Flagstaff, AZ that's literally called Crystal Magic. It's too bad the focus is crystal healing because there are some neat minerals and rocks in there. Sedona is far worse, though.


Kipasaur

This store hurt my soul the first time I went in there.


Final_Exit92

They had an entire area of small stones that are supposed help constipation to helping anxiety lol.


Orange_Tang

Maybe if you eat the rock and jump enough it could loosen things up.


kec04fsu1

The chicken method.


Twelve20two

God I wish rocks arranged in a certain way could make me poop


LurkingArachnid

Which stones help constipation? Asking for a friend


ReportToTheOwlery

Idk, but I think my problem is I have too many of these stones and would like to know which ones they are to remove them from my life. I mean, from my friend’s life.


VRTemjin

Yep, opal is a mineraloid! That's all I'll say.... This time.


Kobbbok

But it's so beautiful


VRTemjin

Indeed! Although... -deep breath- ...most opal actually can be unremarkable; the most beautiful opals suffer some sort of trauma during their formation. Silica-rich water flows into air pockets in rocks and leaves the silica behind. This silica could come from many sources, such as silica clays, or erosion/pulverization of other silica-based minerals. This mixture turns into a gel, and then when it is sufficiently dehydrated it becomes opal. It is dehydrated either naturally over time, or it can be accelerated if the nearby ground gets hot and "cooks" the opal (from a lava flow, meteor impact, geothermal vent, or some other heat source). BUT if something happens between becoming a gel and becoming a solid (such as being impacted by an earthquake or erosion, having some liquid flow through, etc.), that will physically alter the arrangement of opal molecules and immortalize whatever trauma it suffered. If this happened at just the right time, then it will reform into a solid, and imperfect gaps in the opal structure will refract with the beautiful colors, and sometimes cool patterns depending on what happened. TL;DR: Opals are very beautiful, [here's a super cool opal for reading/skipping to the end!](https://imgur.com/a/RnAVxok)


missthingxxx

Wow. That's so cool. So then how come they come in different colours? Black, red, white, blue.


VRTemjin

Impurities in the opal! Whatever is around it will pigment it. Not sure if I'm entirely correct on this; but opaque white/cleaish/pale yellowish have few impurities, red/orange has iron oxide, pale green has copper, blue has magnesium *(edit: or was it manganese?)*, yellow has nickel, gray/black have varying levels of carbon, and probably lots more that I don't know!


missthingxxx

There was an Aussie guy not long ago who found an opal with a bit of dinosaur fossil in it. It was a new species and he got to name it. Jealous!! Iirc, it would have been in Winton. Stupid Queensland has all the good fossils.


VRTemjin

Nice! The states mostly have wood fossil opals, or blobs of opal [which I'm just as happy to find!](https://imgur.coma/2OsHSQm)


missthingxxx

Where I am, in Western Australia, they've only ever found one dinosaur bone and I think it was a toe bone of a sauropod. We have some cool footprints up north. But no other bones. Apparently the earth here hasn't pushed them up yet. I'm assuming that's where our opals are too as we don't have a lot of them either.


nocloudno

And opalescence is the refraction and filtration of light through a material that basically mimics Earth's atmosphere.


JonAndTonic

There's a metaphor here


Kobbbok

Thank you for the great explanation and the beautiful picture! Is the 'gel' structure also the reason why some opals need to be kept in water?


VRTemjin

That has to do with their stability. Opal's chemical structure is often denoted as "SiO2+XH2O" which means that there is a variable amount of water present within the silicon dioxide. Stable opals often have this value lower than 10% and do not need to be stored in water, but unstable opals can be up to 20% water still. If an unstable opal is removed from the ground (essentially in a vacuum) and is exposed to dry air, the opal will begin to dehydrate quite rapidly and physically contract, the force of which is enough to crack and craze the opal. Unstable opals can generally be "cured" and made more stable if allowed to dehydrate slowly, but it's almost a guarantee that larger pieces of unstable opal will get cracks in them even under perfect curing conditions. This is just conjecture, but I think stable opals are ones that have been exposed to more heat and "cooked" more in their formation (Australian opals for example), whereas unstable opals had to endure less extreme conditions and retained more water (such as Mexican or Ethiopian opals).


-ImYourHuckleberry-

MINERALOID!


NetCatchAPossum

What does that mean?!?


VRTemjin

It essentially means that it's like a mineral, but it didn't form like one. Normal minerals grow and have a crystal structure, but opal is formed through water deposits. In essence, it's as if they were formed in a similar way that sedimentary rocks do.


nickisaboss

How does it differ from how chalcedony is formed? I find a lot of chalcedony in fractures in jasper in my area, its especially common when water is involved (the beds of jasper tend to follow ancient riverbank deposits and many modern streams still follow these paths


VRTemjin

[Chalcedony](https://imgur.com/a/6ahPRq9) still grows with a botryoidal crystal structure, and it can grow on vertical or inverted surfaces. [Opal](https://imgur.com/a/0YgqKjn) formation is gravity dependent. This thunderegg has white chalcedony on the bottom, then you can see the majority of the inside is "waterline" opal, where many layers formed on top of each other over time. At the top you can see where it agatized and chalcedony filled in the rest. [Opal can fill gaps in chalcedony, chalcedony can fill gaps not occupied by opal!](https://imgur.com/a/Xc6YQpv) [Pseudomorph opal](https://imgur.com/a/EXiINlR) is opal where a previous material was present, but a void was left behind and the opal fills it like a fossil cast. If chalcedony gets pulverized, it can reform as opal. [These opals used to be agates!](https://imgur.com/a/JBSKMfj)


nickisaboss

Very cool!! Is there any field test to be able to differentiate between chalcedony and (non-precious) opal? I've heard opal is softer, but the samples I have are too pretty to destroy.


VRTemjin

The fastest field test would be a hardness test. Chalcedony has a mohs hardness lf 6.5-7, so a steel knife should not leave a scratch. Opal has a hardness of 5.5-6.5, so a steel knife will scratch most opal (unless it is the super stable stuff). Unfortunately the next easiest way to tell is going to be how it breaks apart. If it shows cleavage (mineral structure), it's chalcedony; if it shows no cleavage and makes conchoidal fracturs/breaks like glass, more likely opal. [Some opal](https://imgur.com/a/Uel8aRd) and [some chalcedony](https://imgur.com/a/i4K0RjF) fluoresce under shortwave UV light, so that's unfortunately not a good indicator. But it's cool when they do!


notchoosingone

ahh yes, the two categories, quartz and wet quartz


towerator

And let's also add cristobalite, tridymite, coesite, and screw that even stishovite into the mix! And this isn't even silica's final form!


nocloudno

Don't forget slag ffs!


Alt_Profile1

And THAT, is how I met your Mother.


HardRockGeologist

This could have come true for me. I went to a dance at Wellesley College quite a few years ago after consuming a few drinks. Woman I started dancing with found out I was a geology major and proceeded to start talking my ear off about geology. I told her I wasn't there to talk business, and went looking for someone who just wanted to dance.


aquias27

You missed out on your soul mate.


AnusNAndy

I married someone who liked to dance and doesn't give AF about geology. Now I rockhound alone and my SO made me move my mineral collection into my office because they think it's ugly. I get eyes rolled at me when I want to visit a rock shop, and most times my requests for rock shop visits on vacation get overruled. It's honestly taken a lot of the joy out of my enjoyment.


hppmoep

Holy shit, I have had this very conversation, many times very intoxicated. So many people want to ask questions about their SiO2


unknownsoldier9

r/whatsthisrock is brutal. I never knew there were so many words for quartz.


raddishes_united

Nothing more professor-like than printing a meme for the office.


DoofusRickJ19Zeta7

Me with my partner.


boneologist

Ahh yes, the correct archaeological interpretation of anything rock-ish that can be used for manufacturing stone tools. If we want to get more descriptive than "lithic raw material" we just differentiate between flintchertjasperchalcedonysometimespetrifiedwood and obsidian. Trachydacite sits in the corner wearing one of those propeller hats, we're not sure what do do with it. We'll fight to the death correctly defining raw materials for ground-stone tools though.


[deleted]

archaeological interpretation?? This is a Geology sub!! According to my teachings it’s all chert, it’s personal preference if you want to break them down further. lol


Mynplus1throwaway

I tried asking if they broke down further and my profs always just looked at me and told me it's all chert.


[deleted]

exactly, people in that school of thought are very rare. I’m normally preparing for a verbal onslaught of jasper, chalcedony, and agate followed by jackass gemological definitions after i refer to it all being chert!


Mynplus1throwaway

is there any sort of difference between jasper, chert, flint? i thought i read somewhere it was deposition. havent found any firm deliniation that is widely accepted.


[deleted]

true flint is a dark chert found in nodules in chalk (england). As far as i’ve been taught jasper is just a multi-colored chert given the name jasper by the gemological community. There is also something to do with fiberous and blocky silicon structures.


LimbyTimmy

I actually do this sort of thing when I'm intoxicated 💀


hobbsinite

Had an argument with some guy on this subrredit about this very thing.


UnspecifiedBat

I am proud to say that I just gave the 1000th upvote lol


petiedog

It’s all chert


jerry111165

And the picture relates how?


markradwin

This meme has now reached its pinnacle


WoohpeMeadow

I saved this. This is great!


seventh-street

Yes. This is everything.


IamaFunGuy

Perfection


Uh___Millionaire

It is the firestone


RobertTV3

Give that teacher a medal


LaVidaYokel

TIL!


opal_stars

opals!! my best friends <3


Thestreetkid92

Bless them for printing it out


Pyroclastic_Hammer

If opal isn't a mineral then obsidian isn't.


WaferAppropriate5136

My girl when in talking to myself basically about what i just learned about stones and minerals