Opal: the Most Flamboyant Gem [Gem Buyer's Guide]
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- เผยแพร่เมื่อ 27 ม.ค. 2021
- A peculiar gem and almost ALWAYS one of a kind, Opal is a gem that has enjoyed great popularity for a long while. Where does this fabulous and flamboyant play of colour come from? What makes one higher VALUE than the other and what are the fakes? Find out in today's episode of Gemology for Schmucks.
For more articles on gemology and investing in gemstones, and to contact me directly, visit gemshepherd.com
For those interested in seeing prices and dimensions on the stones shown today, you are welcome to check out the companion video on Nazo Anna's channel:
• Nazo Anna Opals
Any inquiry emails are welcome at Nazoannagems@gmail.com
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I love your films
I'm glad you enjoy my work, and i appreciate your enthusiasm for precious opal. Its a category of stone much like pearls and diamonds in that "it's totally its own thing and there is a LOT to know"
You made a lot of good points in your presentation here👍
For clarifications sake, opal is generally considered a mineraloid.
For little reason other than to make use of the many hours of research I've invested in opals, I'll leave a bit of unsolicited info related to the topic.
There are many different causes for the formation of opal around the world, some being of volcanic origin and others considered sedimentary, thus the varying appearance and types of opal found around the world.
It could also be hypothesized that in some cases opals could have a partially bio-organic origin as the silica responsible for the genesis of such opals beneath ancient seas/oceans may in fact have come from siliceous oozes accumulated from the remains of microbes such as radiolarians.
'this has previously been proven to be the source of the silica depositions responsible for the semi-precious stone mookaite', while mookaite isn't found in the same location as precious opal is in Australia, it is similarly characterised by microscopic silica deposition, similarly tigers eye can also in many cases be attributed to bio-accumulation from ancient microbial ecology.
No doubt this is simply a hypothesis though as the presentation of silica as spherules in sedimentary opal makes determination of the silicas origin all but impossible to ascertain without concrete evidence pointing towards ba particular source, silicates are generally quite resistant to weathering though, hence my personal view that a bio-mineral origin may be quite plausible given the known examples of similar accumulations in other similar environments.
The origin of such silica spherules in volcanic opal however, are more readily attributed to cristobalite, with cristobalite being a common constituent in silica rich volcanic ash it's understandably the most likely source.
The opal in Australia whilst commonly being of the sedimentary type can also but more rarely be of volcanic origin, 'contra-luz' opals like those typically found in Nevada are generally seen in the volcanic material more so than in any sedimentary type opals.
Generally speaking, sedimentary opals are more often associated with hydrostability than their volcanic counterparts, though, there are exceptions, the overall stability ultimately having more to do with the water content and porosity.
You've taken quite the deep dive into the opal world. Great to see, as its suuuuch a different world from the crystalline gems.
My favorite is black opal from lightning ridge. Just magnificent
They can indeed magnificent. Opal is such a different world. Thinking about the value points of this category of stone is soooo different from crystalline gems or even pearls.
A very good explanation of opal, interesting. It is one of my least favourite stones, but I enjoy learning about it, with you clear description of each. Fire opal , I could go there…
Opal is a strongly polarizing stone. It's a favourite of many, and untouchable as a leper to others. Cheers~
Korat has a fantastic petrified wood museum. A massive specimen inside the museum is loaded with opal.
Thanks for the suggestion - i've not yet visited Korat. Not so far from BKK
Thanks for giving us that info🙂👍🏾
My pleasure, Stu
WOOOOOW I mention and you deliver
I was in the process of editing when you commented a few days ago, and it was like .... FATE!! XD
@@GemologyforSchmucks its perfect! Bringing the world of gemology to the everyday person is amazing enough.
Then you go ahead and include opal, I've sent this around the opal community.
I cant wait until I have the time to binge watch all your content.
Can you make a separate video on every gemstone similar to this Opal video? It would be great playlist for schmucks like me. Adding pictures of variety of a gemstone helps a lot. Thanks again!
I will do my best Tushar ^_^ I'm glad that these videos have served you.
@@GemologyforSchmucks yes they are. My family has been into gold and silver jewellery from four generations. Now I'm trying to learn about gemology in order to adapt to consumer preferences. Your videos are a guiding light to me.
Do let me know if you visit India, maybe I can learn more. Cheers mate!
Very interesting!
Glad you enjoyed, Stephanie~
Love opal!!! I didn't know about synthetic opals, how common are they on the market? And is there a simple way to identify that they are synthetic?
once you've seen a few pieces and have seen the rough "bricks" its pretty obvious to the eye. There are some natural patterns that look similar, but this looks too "organized" compared to most natural opals
I have a ring with a small ethiopian opal in an oval brilliant cut. I've noticed that if I look through the stone at a strong light source from certain angles, the play of color completely disappears and all I see is a reddish transluscent stone, somewhat akin to fire opal; despite the stone looking milky white under regular lighting and conditions and displaying very pretty play of color effects.
is that a consequence on the cut (I take most opals are made into cabochons)? Also since opal workdsloke anatural diffraction array I'd imagine the transluscent axises must be those normal to the planes of silica?
There's all sort of ethiopian opal including the fire type... They are often wonderful and cheap but prone to cracking and treatment are pwetty much always showing traces so... Apparently the elusive non-hydrophane Ethiopian opals are way better, similar to the best Australian opal but I have yet to find a eBay seller who sell top grade of this stuff 🙄
That treated dime piece of opal is the kind of tourist deception people buy at flea market thinking they just found the best colored black opal. I get ppl showing me stuff like this expecting gold on a monthly basis 😂
Opal doublets are a nice appearance for a low low price, but at the end of the day... it just ain't rare.
@@GemologyforSchmucks But some doublets can get to really high prices. Black Opal with good colour is rare even in doublet. Or maybe it's by budget for opals thats telling me its rare 😂
@@aniare8186 Sure ~ there are doublets that can be quite costly, but if we compare those (even for the same face appearance, if you could find two black opals that even remotely resembled each other...🙄️) The solid opals are going to out price the doublets well and away. Quality is quality, yes, but quality plus rarity is another beast.
I think the word you are looking for to descripe opal as not a mineral is aggregate?
Its a good word, but still not specific enough for this purpose. It is an aggregate, yes, but so is jadeite, nephrite, lapis lazuli and many other rocks, microcrystalline and cryptocrystalline gem materials. Those are still composed of teeny tiny crystals, where as opal is not crystalline on any level. Thx for the comment.
what you showed is boulder matrix opal , not boulder opal , the price between the two is night and day
Hi James,
Thanks for bringing up this point James, and I'd love to hear how you would distinguish these two types of opal. Perhaps its simply because Australian opals are so few and far between in Bangkok, but i've not yet heard someone make a distinction between the two. In fact, such close terms would make me suspicious of their intentions if they were trying to sell me a stone.
I look forward to the answer and some instruction on how to distinguish boulder opal and boulder matrix opal and the opportunity to learn.
@@GemologyforSchmucks very simple, boulder opal is a layer of opal on iron stone so the stone is completely covered with a layer of opal, boulder matrix has vains and paterns in the iron stone like what you showed, boulder is very expensive, matrix not as much but it can be beautiful
first of all when grading opals it not how derectional or not an opal is, the first thing is the base color from N1to N9, the body tone, we start there, then all other things mater such as how much color , number of colors , and how bright the opal is on a scale of 1 to 5, patern is very importaing but brightness is paramont 5/5 is gem briliant, get your facts straight before posting a video
I appreciate that opals stir up so much passion in you James, and thank you for sharing your expertise on the subject. I'll be the first to say that I have more to learn about many if not all topics in gemology. Fortunately for me, I did make this video, and now I have the fortune to hear your view of what is important in opals and their grading. As to grading systems - for opals I won't speak about the grading system as my experience with them is limited, but in coloured stones in general, grading systems are not unified across the trade as they are with diamonds. They tend to vary a lot depending on which company or trade group made them up. A grading system may be useful for one company or trade group, but the other traders may have their own idiosyncratic system that they prefer. Naturally that was beyond the scope and intention of this video.
Thanks for your comment, James, and for the opportunity to learn.
@@GemologyforSchmucks compared to opal colored stones are very easy to grade, it comes down to one thing its all about color and like diamonds the clarity cut and size all matter but what matters most is purity and saturation of color and having the right tone not too light not too dark just right, those gems get the highest price, with opal there are many things to consider more then for any other gem, just to name some, base color, how many colors , what are the most dominent colors, how saturated is the stone, what percent of the stone shows color, is it diractional or non diractional, how thick is the color bar, how thick is the opal, what pattern does it have, how bright is the opal , and you have to know witch of these add value or subtract value , much to worry about compared to other gems, lol