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Are these opal?

Hi im new to the gem world and have been working on different stones iv found over time. id like peoples opinion on what they believe these might be. sorry for the bad pictures they dont do justice.






thank you in andvance i also have opalized wood i think.with a rolling fire. i will post about that later.

My guess is NO, neither piece shows the characteristic “opalescence” - the pearly luster with iridescent patches that is essential to calling a material opal. I would guess that the first piece is crystalline quartz and the second piece is a polished marble. Both pieces have the glitter that is characteristic of a “crystalline” texture" - small crystals that are locked together like a jigsaw puzzle.
Opal is noncrystalline. You can use a good steel nail to assist in checking these suggested identifications. Find a very obscure spot and see if you can make a very small scratch on the material. Quartz has a hardness of 7 (nail is about 5.5) and the marble is made of calcite with H=3. So the marble will scratch and the quartz will not.

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ill have to get a better video for you. there isnt a crystal structure. iv used a table lap up to 1000 grit on these. and spent many hours on two of them.


the last picture of the skinny one started like this and thats what i ended up with the skinny one.
again on this picture of the rough stone i skinned it broke a piece off to play with. also it has been in a cool dry place for well over a month.
tbh i have thought of these beiing a quartzite with small opal areas. idk i will be investing in a decent camera so i can get magnified pictures.


i have one that at the right angle the whole thing goes silver no other color. of course it is only about a carat if that

A refractometer would be a better choice than a better camera.Pictures are only educated guess.

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No resemblance to opal what so ever, looks more like a quartz.

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yes i had to educate myself more. what i dont under stand is the phenomenon that i keep finding. like in this one.


i have a video of this one but cant seem to upload it. this is the one that will turn silver looking as it moves side to side.
Screenshot 2022-11-11 at 04-10-52 Facebook
Screenshot 2022-11-11 at 04-11-16 Facebook
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iv even had some come out with a rainbow of colors the same way this one came with silvery flash.
i do have a theory. these stones came from a place where the guy was very private about his works. he talked about rocks and heat and i seen paper work for a 20,000$ stone. unfourtanitly i was young and passed it off as old crazy talk. the size of the stone i have that does the silvery flash and some times the raindbow is the size of a persons head if not slightly bigger i had two of them the other i busted with a hammer it was (black red and white in layers) and began working on small pieces to educate my self on lapidary work. this stuff is hard its scratches quartz crystals that i have with ease. when i take my crystal and attemp to scratch my unknowen stones aftert iv polished them it leaves a white streak that wipes off clean with no make left behind, could this old man knew how to do the cvd method??? i honestly belived he did. these are granual type stones but when worked on properly there is only one way to notice it and its from the girdle. i live in north west florida. we dont have stones at these sizes. unless there down in the bottom of the black marshes. i have found opal here. but as stated by otheres there isnt any opal that look like these. that iv been able to find.


the red and black show the same effect but stronger. also some pink came out of all the red and black and white stone. i honestly think i need to create a new post now i think iv gotten off the topic this was ment for :frowning: mybad

You could try unloading the video to youtube, then putting a link to it here, i must admit, i’m curious too see it myself.

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https://youtube.com/shorts/NOenKYln82g?feature=share
i named it the silver flash. sorry for the quality

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That worked, I’ve some Feldspar somewhere that looks similar, but if your hardness test is right, it can’t be that.
Cancels out Opal too.

it wont be right now. but later today ill get a video of me doing a scratch test to quartz crystals i have.

If the material scratches quartz it is not opal, opal at Moh 5 - 6.5 is softer than quartz at 7. The dispersion effect you describe is common in a number of crystals.

Generally, there are several simple tests you can carry out on unknown stones, Firstly, hardness using a knife (as previously suggested), and also a quartz crystal. Secondly, density. Is it heavier than normal rock eg quartz. Thirdly, when scratched on a white tile, what is the color of the streak? And fourthly, does a drop of strong hydrochloric acid produce a reaction eg bubbles or a change in color or the form of a small sample? The fifth is to hit the stone with a sharp blow to see the way it fractures. If the cleavage is even then it may be a feldspar, if uneven and glass-like it may be quartz. These are all invaluable tests out in the field together with a pocket reference book on minerals. Good luck!

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