Buyer's Guide to Spotting Real & Fake Turquoise.

This video covers several tips to help you figure out whether a piece of "turquoise" you found is real or fake.
This video was made by a geologist who attended Arizona State University.
This video is protected under "fair use". If you see an image and/or video which is your own in this video, and/or think my discussion of a scientific paper (and/or discussion/mentioning of the data/information within a scientific paper) does not fall under the fair use doctrine, and wish for it to be censored or removed, contact me by email at [e-mail] and I will make the necessary changes.
This channel has an etsy store. If you enjoy rocks and minerals, check out prospectingarizona.etsy.com .
#turquoise
Google Earth imagery used in this video: ©Google & Data Providers

[@grumblecroak]

Thank you for getting straight to the point. I've been able to identify that my turquoise necklace has a 90% chance of being genuine, due to the presence of pyrite. I got a loupe and took a really close look, tricky as it's made up of tightly packed rondelles. Very helpful video.

[@ritaduray3732]

Rendy Moondust .......I’ve been collecting TurquoiseJewelry for over65 years... I’ve been selling Native American Indian Jewelry for over 50 yrs... I’ve been making (I’m a silversmith) gemstone jewelry for almost that long. I have always loved my TURQUOISE pieces the most. Older pieces very often came from copper mines in theSW.. Now those mines are closed! The specks of pyrite is more common in newer mined Turquoise -- You will find dark veining that is copper scattered thru these pieces..dark maroon or black veining ( called matrix ) you will find the turquoise color that sometimes is not consistent especially thru larger pieces. This variation is subtle but its there. Gem quality is noticeably heavier that the “lookalikes.” If you’re looking at a beaded necklace the weight is telling! Older Turquoise was often rubbed with bear grease that would deepen the color... it was made before stabilizing became popular. I own a beautiful necklace with multiple separate pieces all natural... From my constant fingering I changed the color from just the oil in my fingers. It became noticeable and I stopped touching it every time I wore it. It’s a signed piece and the maker comes from a well known family of silversmiths. 75% of all the jewelry made in the SW by Natives is now stabilized. 75%is also dyed .This allows them to use a lesser grade of stone and because “gem quality turquoise “ is sold like diamonds “ by the carat weight the PRICE is your biggest indicator.Basically Sterling is marked 925 and that means 92.5% is pure silver. Older SW jewelry is often made from old silver coins.Coin silver is 90% pure. I own some fabulous Indian coin silver pieces.Now it’s all stamped and signed.(unless it’s from China and they’re the biggest liars in the world ... they stamp it 925 and its Copper and then CHROMED like a car bumper) If you love this very American Artistic jewelry ( they learned the art from our neighbors -Mexican plateros-silversmiths- ) I suggest you spend some time in the local library looking at books and reading... there are 3 styles you will see right away -- Lots of beautiful silver work and design with big stones... that’s Navajo , then there is a more intricate style consisting of clusters of small stones in different designs that’s Zuni And then there is Hopi Silver jewelry... the carved look in silver , the stone is an accent if there is one -the design tells a story .. it’s mystical and spiritual, completely different than their brothers ... if the “team” are a mixed marriage both smith will sign and they might even have a registered sign you’ll find in a book of Native hallmarks..Newly made Indian jewelry , signed -showing off beautiful gem grade stones is Expensive and it should be..Because it’s totally original and will only become more valuable with time. Ps - it’s very difficult to find knowledgeable people who specialize in Native Jewelry -if you’re luck enough to visit out west any Indian Museum can point you to someone locally who can appraise and give you good info about the piece or pieces you own.

[@CricketsBay]

Thank you for sharing your knowledge.

[@cmcer1995]

@@ritaduray3732 You sure seem to know a lot about Turquoise, but with all those years of experience I can see why. I even suspect you are even correct, because you are not even advertising, your just offering free information. I will save this information for the future. Thanks for the video.

[@slayer7682]

I don't no why this was in my recommendation but I enjoyed it maybe this knowledge will come in hand

[@theofficialdiamondlou2418]

Ditto

[@Emsie76]

Yup me too.

[@ronwhite8324]

Me, too.

[@flufflepuffle]

My mom likes turquoise, so maybe I'll get to whip this tidbit of knowledge out, haha.

[@flclub54]

I concur

[@1980rlquinn]

I just love how the presence of "fool's gold" is indicative of a genuine stone.

[@partysuvius]

Pyrite’s my favorite metal. It’s made of iron, which can be very very useful. Unfortunately, I don’t think you can melt it down to turn into jewelry or anything and still have that golden color, which ig is why it’s considered useless for jewelry unless it’s used inlaid in other metals as a single piece of jewelry.

[@munirahbakar4123]

Even a fool has its use.

[@amypanddirtytoo1926]

@@partysuvius I think it's gorgeous in its own right. And maybe having to use it the way it has formed is what can make it really unique for jewelry? Like just having a pair of earrings that are just two solid nuggets of pyrite, perfectly mismatched, kwim?

[@seichipauljimenez977]

@@partysuvius and sometimes the unusual cube-like ores.

[@zeaxanthinepoxidase]

@@amypanddirtytoo1926 that sounds like a cool idea but i am afraid the nuggets would be too heavy

[@TM-tx9ct]

You didn't mention reconstituted turquoise, where genuine turquoise is ground up and resin is added to make a stone shape again. Veins are added through it and pyrite and or copper is run through it. Mojave turquoise is usually created this way and gives a very stunning effect. It is real turquoise, very beautiful but has had a helping and should be sold as reconstituted turquoise. Also not only turquoise has pyrite, lapis lazuli and other gemstone also have pyrite inclusions.

[@jjbentley9]

Yes your correct about the pyrite being on other stones such as lapis. That's what gives lapis it's golden luster.

[@user-kp7gb4hs8q]

M P , I see an opportunity for you to make the video about resin

[@blueberry464]

Are other gemstones with pyrite similar enough in color to turquoise to be confusing? I'd expect lapis lazuli would be easy to distinguish from turquoise.

[@Namron9797]

@@blueberry464 It is very easy to distinguish for anyone who knows anything about either stone. What people often confuse are Lapis and Sodalite.

[@sjwarialaw8155]

@@Namron9797 yeah lapis and sodalite can be very hard to distinguish for an untrained eye, I might be wrong but Lapis has golden spots and Sodalite has white spots.

[@plsletmerest5113]

Further confirms my theory that absolutely anything can be entertaining to learn about as long as the presenter is well informed and enthusiastic about the topic

[@grmph]

ayy, same pfp!

[@MM-jf1me]

Very interesting video! I'm not sure why or how the KZbin algorithm decided to recommend your video to me, but I'm glad it did! Thank you for showing multiple examples and keeping your video straight to the point--very useful should I ever see any turquoise (or a stone being passed off as turquoise in real life).

[@GeologyHub]

Glad I could help! :) I was also amused to see that the algorithm decided to show one of my older videos

[@williamchamberlain2263]

I missed the Recommendation surge 3 weeks ago; might be another one today.

[@MoogieB]

Know that if the price is low, it’s almost positively fake. Any treatments should be noted such as dyed & stabilized. Buy from a reputable dealer. Sleeping Beauty turquoise is gorgeous & very expensive because the mine is closed. I love real turquoise!

[@suzannelawson9215]

How do you find a reputable seller? I don't know anyone personally that has ever bought turquoise, so don't have any referrals to be advised about. I am looking to buyna simple necklace, not anything too elaborate.

[@shakeme3290]

@@suzannelawson9215 I’m looking for a reputable dealer also.. maybe I should try a gem show? Anyone?

[@Namron9797]

You actually do not have to notify of turquoise treatments because most of it in market is treated in some way to stabilize it. If the practice is common then it is considered general knowledge and therefore does not need to be disclosed. I tell people ASSUME it is treated unless it is stated otherwise. The only exception is if it is treated and you say it isn't, then it's illegal.

[@MoogieB]

@@Namron9797 thanks for the clarification. So, if it’s a generally used treatment or enhancement, it doesn’t have to be disclosed? Such as heat treating citrine or quartz?

[@EternalShadow1667]

@@shakeme3290 I’d say go online and spend an hour or so searching for a dedicated turquoise community or something, there must be at least several forums dedicated to the stuff. Once you find one, hunt around for reputable sellers, they’re probably pretty well known and you’ll find them quickly. Probably. Just my take on it

[@Thalpy]

I see the algorithm has decided to punish salesmen of false turquoise.

[@cijmo]

I worked at a thrift store and gem hunters etc would come in. Sometimes you can get the real deal at thrift stores because the person doing the sorting doesn't realise it ... but if you could only see the number of people doing the spit test or dragging pearls across their teeth...and we don't clean them every time.

[@katydid5088]

Eww! My general rule is that if somone tells me to lick something, I approach the offer with the same scepticism as I did when my brother told me to lick a chocolate powder sample. Don't lick it don't touch it. I know taste is a valid way to test some minerals but all the same I'll pass.

[@Namron9797]

The pearls test IS real though. I won't do it personally cause...ick...but it does work and is accurate.

[@cijmo]

@@Namron9797 Oh I know it's real (I don't work there anymore, I'm sure the game has changed now!). I just can't imagine someone not thinking about the person 5 minutes ago who scraped them across their teeth. We like to think people have the same hygiene as we do but it's not always so.

[@adelinaclonts7004]

Lol

[@neynahnehnah1485]

@@Namron9797 how do you do it?

[@carolynclink8443]

Thank you -- this is the most-helpful of the videos I have seen on this topic! I am now convinced my thrift-store find (Taxco sterling bracelet with 3 "turquoise" stones) is not real turquoise. The uniform color and the skinny veins give it away. Thank you!

[@GeologyHub]

Glad I could help :)

[@JEBavido]

Informative. Thank you. I am blessed to have turquoise from Iraq-- bought there almost 50 years ago-- which is pure blue with no veins. I have to enjoy privately that it's real turquoise because casual observers assume the pieces are just plastic! LOL!

[@almclester]

Persian turquoise is exquisite. Lucky you!

[@johncampbell829]

So you have an easily faked blue rock...that's just got to be the highlight of your life!

[@JEBavido]

@@johncampbell829 , lol! Since it was a gift to my mom from my dad back when he worked in Iran it has a lot of value, to me. I hesitate to say I'd buy one myself for just the reason you've stated.

[@EMRAE_8]

The turquoise from that area is the highest grade turquoise in the world.

[@neynahnehnah1485]

@@almclester true. Iran, Khorasan has the best turquoise in the world and because Iraq was part of Iran they have it too. They way Iraqis keep them as rings is interesting.

[@Cindy-bn7cr]

Sometimes turquoise chips are ground up and glued back to form a larger stone. It is not always disclosed.

[@ritaduray3732]

That’s a common practice and one I always question--it’s called reconstituted and it should always be disclosed ... if the seller says they “don’t know “...walk away...reliable sources will mark turquoise with D/S (dyed & stabilized) ASBL (assembled) IMIT (imitation)Quality natural stones are heavy and sold by carat weight.Sleeping Beauty is a mine still producing beautiful Turquoise. We also have quality stones coming from Thailand.

[@Namron9797]

@@ritaduray3732 Yeah...no they are not. Most turquoise in the market is stabilized/treated in some way just like most gemstones are. It is so common that it does not have to be legally disclosed unless asked. I have never in my life seen "marked" turquoise jewelry. I always tell people 2 things. 1. Assume everything is treated in some way unless stated otherwise. 2. If it is pretty, does it really matter? Most treatments done to stones are done to make them more durable and protect it. It also allows "the common man" financial access to nice things instead of garbage or nothing at all.

[@williamchamberlain2263]

Alternative title: "How to make your imitation more convincing"

[@themurrrr]

0:51 This may not be turquoise, but it’s gorgeous!

[@lornae8683]

Thank you so much for not taking 60 minutes to explain what only can take 3. You have made a very educational and straight to the point video .

[@execbum1]

Thanks for this. I'm pretty sure my turquoise stone is dyed howlite. Bit annoyed that I wasted money on it - I wish I'd seen this before. I'm going to use this as a guide before buying anymore.

[@GeologyHub]

I also made a similar mistake early on in my mineral collection. A stone I bought for $14 was in fact dyed howlite

[@user-uc9yh9vw9e]

​@GeologyHub please make a video on how to recognise a stablized turquoise

[@rebawasswass3716]

I've been purchasing my turquoise from The Silver Tribe. They lay out all info on each product and it is stamped for the silver and stamped by the artist. They aren't cheap but I've never been disappointed in any of my purchases.

[@Pashasmom1]

I have bought turquoise stones to make my own jewelry at The Turquoise Chick. It's all real and they will buy the turquoise back if you don't like it. They have all kinds from the different mines. Sleeping Beauty mine was closed due to overmining.

[@tvdvd8661]

Yup turquoise is not cheap

[@oscarmedina1597]

An unscrupulous seller once tried to pass larimar as turquoise; of course, he had no idea what larimar is and sold me the piece at a great discount thinking that it was cheaper than turquoise.

[@ritaduray3732]

Oscar...If the Larimar was a nice shade of Blue it’s a very Valuable stone and is only found in the Caribbean Islands. So you probably got a good deal !

[@Pashasmom1]

@@ritaduray3732 I thought Larimar was found in Dominican Republic only. And yes, the bluer it is, the more valuable it is.

[@canadiangemstones7636]

@heart snob Larimar is a trade name for pectolite, a common mineral found in many places around the world.

[@onecuet]

Larimar looks nothing like Turquoise. I love Larimar. I have multiple jewelery items. The best turquoise is Sleeping Beauty. Which wasn't named in this video. It's a brighter more blue turquoise with no veins.

[@mircat28]

@@canadiangemstones7636 Larimar is a rare, sky-blue colored gemstone. It is a variety of the mineral pectolite. While pectolite is usually gray, blue Larimar gets its color from copper impurities. ... To date, blue Larimar has only been found in one location in the world: the Dominican Republic, and some other parts of the Caribbean. Oct 2, 2017 pinkkarma.com › blog › why... Why is Larimar Jewelry so Special? | PK Gal Blog - Pink Karma

[@diannebartkus9893]

Loved this video. I buy gemstones for jewelry and it can be a challenging thing as many of us can imagine (smile)

[@GeologyHub]

Also, I haven’t in my work seen quite as many other gemstones we as universally sold as fakes (other than pearls)

[@froznpyro]

Ah yes. The KZbin algorithm has brought us all together to brush up on our shiny gem knowledge before society crumbles & we revert back to using these as a rudimentary currency.

[@christineallen4790]

Awesome, i have been making jewelry for a month and a half so it is good to see how to tell the fakes when i go to buy stones and such for the jewelry i make!

[@apollofell3925]

Here's me realizing I've never seen real turquoise in my entire life

[@NinaNooneknows]

This was super helpful and informative! Thank you for showing lots of examples and getting straight to the point. :) Do you think you might be able to do a similar video on genuine vs. treated ametrine (and maybe citrine by itself)? I’ve learned to tell apart the most disrespectful fakes, but especially with some tumbled stones I’m still not sure!

[@genehasenbuhler2594]

This was great info, don't know why I didn't see this a yr ago but I'm glad I found it now!

[@hazel555]

Interesting information. I have to disagree with your claim that a turquoise seller should know where a particular piece was mined. There are a lot of different outlets for buying turquoise, and unless the seller bought directly from that mining operation or the info accompanies the piece, they're probably not going to have any idea of it's origin.

[@danamichelle1290]

I think his intention was to promote authentic sellers, rather than items that have changed hands a lot. If the item is of quality, that info will be available.

[@Namron9797]

@@danamichelle1290 LMAO. No it won't! There are SOME types of turquoise that is distinct enough for a highly knowledgeable seller to know where it came from, but most of it....no. And due to the new Chinese mines, it makes even that difficult!

[@danamichelle1290]

@@Namron9797 Reread. And it's *are. The types ARE distinct.

[@melanie.l6282]

Petrichor i agree totally

[@christinehutchins123]

Exactly! How many older pieces out there???? I say most won't have this information.

[@tommunyon2874]

Nice stuff to know. As one who spent their childhood a stone's throw from Santa Fe, where I must have viewed thousands of pieces of turquoise jewelry under the portale of The Governor's palace, I only questioned the authenticity of the stone if I was someplace else and the dealer was unfamiliar.

[@GingerMafia48]

Also a geology grad! Great video, gonna share it with a couple of my professors. I enjoy the short and interesting videos you make!

[@kerielwatson3197]

Do you have similar videos on other stones? Lapis lazuli, Citrine, Ametrine etc?

[@AA-vr8ve]

So really random and you prob don't care but citrine tastes different from other rocks

[@papercranes9500]

@@AA-vr8ve is it safe?? to lick?????

[@AA-vr8ve]

@@papercranes9500 oh heck naw lapis lazuli is toxic af

[@c-man5679]

So toxic u can start to hallucinate. I like to put small pieces in my lip, like chew. 🥴

[@Apostate_ofmind]

@@AA-vr8ve oh damn 😳

[@catgirlfield]

I have gotten this recommended to me 5 different times in the past two weeks and I feel like if I don't watch it now I'm just doing a genuine disservice to you.

[@richardmotivationmolina8179]

Very nice examples thank you 😊

[@lolothesilly]

Neat! I always loved turquoise and was disappointed when i learned years ago that most "turquoise" in stores for low prices is just dyed howlite or other stones. I always wondered how to tell the difference. Thanks so much for this video!

[@LEDewey_MD]

This video came up on a random "play list", but I enjoyed it very much. I actually make jewelry as a hobby, and found this info to be helpful!

[@FindsofYesterday]

Thank you for showing the differences. I appreciate it!

[@samer537]

Very good video. Thank you very much!!!

[@yoco3447]

Excellent video! Thank you. You also have beautiful jewelry and stones for sale at etsy.

[@1lomi901]

Hello, why are you in my recommendation. This is a nice authentic video that get straight to the point. Thanks for that

[@tdelphia1]

Informative and succinct! Excellent!

[@seekthuth2817]

This is the epitome of "seemingly useless knowledge that will come in handy in the weirdest place."

[@speccysquaregolike9629]

I'm not even looking to buy turquoise, but it's a good video. Quick and straight to the point.

[@cmcer1995]

Great video on Turquoise recognition. Amazing what people will go through to take advantage of one another.

[@brendareed8412]

Interesting! Thank you for posting this.

[@pashtunchannel1038]

The pyrite is like glitter ✨ in the rock

[@kathleenmayhugh2246]

Turquoise has always been a hard gem for me to understand, because no one can tell you where a random piece has come from, therefore like antiques, provenance is vital.

[@HipFlippinMamma-Kelly]

Awesome info! THANKYOU!

[@mutualbeard]

Thank you for sharing this. Knowledge is a great weapon against scams.

[@CeruleanSeal]

Thank you algorithm. This info has come very in handy. I will remember this in the event I ever consider buying turquoise (though I probably won't).

[@believegod2573]

Thank you very much for your instructional video. It is very helpful. It has solved the identification problem that I have been troubled by and I have benefited a lot.

[@S1L3NTG4M3R]

Thank you for getting straight to the point!

[@unmellowyellow]

This was an excellent video. Thank you!

[@jeezuschrist9887]

I have been wondering about this for years! Then, bam! In my recommended. Thanks!

[@adamdavis8082]

Very informative! Thank you

[@garywardsr.4719]

wow never knew that , thanks really informative, and to the point

[@Sceptar]

Great subject...really interesting where all the semi-precious stones come from and how to tell the difference

[@kreyperez9842]

Learning how to better identify my favorite stone makes me appreciate it more

[@mr.iforgot3062]

Excellent! Mr. Kelley thanks you!

[@WakkasLove]

Very useful! Thank you!

[@crystaleevee1334]

Not sure why this popped up in my feed, but it was still interesting nonetheless, and gave me a nice little flashback to the time I spent with my father. During his younger years, he would make turquoise jewelry for a living, he even still had a collection of older pieces that he made and leftover stones. He would often show them to me with such excitement, and would go into great detail about which part of Arizona each stone came from. I miss hearing him talk about that stuff. These days I keep seeing more “turquoise” things pop up in places, and I can always tell right away it wasn’t right, as it looked completely different from the real stuff from my father’s collection. What was new to me here is that I had no idea what the different varieties of “turquoise” where. So it was neat hearing what the actual names of those stones are. It’s hard to believe a stone that was once so commonplace (least here in the southwest), is now being constantly faked.

[@rodneybrennan478]

Thank you so much for the great video.

[@MrGekken]

Thank you for the short but very informative video. I watched a lot of longer videos on how to recognize turquoise by destroying them, here in 3 minutes I learned more :)

[@nonmihiseddeo4181]

I have some big, showy pieces of turquoise from an artisan in Kingman, Arizona USA. He created the pieces to my specifications, and the pendant necklace and earrings, featuring turquoise pieces one-inch-long each, set in silver also mined locally, are my favorite summer pieces. EDIT: I also have some plastic pieces that look like turquoise, which I enjoy wearing (watches and bracelets/anklets).

[@bjebenstein]

Very helpful. Thank you.

[@dr.s.p.]

Very educational. I wish I’d known all this 50 years ago on my first visit to Egypt, where we all got royally ripped off everywhere we went 😂😝

[@asnaghall]

Algorithm: figures out yer Native Algorithm: *finger-guns* I got ya fam

[@dionysus8208]

I may be a freshman who doesn't nor will probably never need this knowledge at all but will i watch this video anyway? Absolutely

[@parsifalkitty5109]

As someone who lives in Turquoise central for the most part. Now I think i'll have more of an appreciation for the state fairs jewlery section. Love the silver work

[@thepwrtank18]

me who has no intention to buy turquoise: hmm, interesting

[@franceschu489]

really useful!!! Thank you very much!!!

[@floramew]

Another viewer who's been recommended via the algorithm... I don't think I've searched yt for rock stuff, but I love geology & am trying to get into identifying, so this is less surprising and more serendipity 👍

[@kimberlyperrotis8962]

Thanks for teaching this urban (San Francisco) geologist more about turquoise.

[@warandragon4713]

Very interesting explanations thank you very much

[@alexn5743]

As an extractive metallurgist I appreciate this video immensely. Especially because ironically I suck at geology and mineral identification.

[@mjmaccabee7252]

Thanks, this is helpful! Could you do one on topaz, including things like "London Blue" and "Rainbow Topaz"?

[@loop78]

Thanks for the video! I make earrings (though haven't used turquoise yet) so this may one day come in handy!

[@dakotarojas22]

Great video thanks!!

[@aliciamersdorf4426]

Thank you for this informative video.

[@The-pf4zy]

I've never really shown much interest in geology and this video somehow got into my recommendations. Not regretting watching this video though!

[@OayxYT]

This is good to know if I ever go shopping for this

[@marilynbaylis524]

Thank you for information!👍

[@chloskyskies4399]

I guess KZbin has determined I shall need this knowledge

[@andreavaldez8104]

This was very helpful.

[@adamstubes]

So helpful!

[@JT-nu1oi]

Thanks for information

[@WangFire]

As someone who lives near abundant turquoise souces I never even thought about them being faked. Turquoise is so common here

[@stephbgg6451]

thank you

[@dat2ra]

Great! Thanks.

[@cheyennevickers4868]

Thank you so much! I love turquoise, and I just went through some of my stones and looked at them and found atleast 4 out of the 15 that weren't actually turquoise! :o thanks again!

[@erin.c92]

I remember going to Bisbee while visiting my grandparents in Arizona. They had numerous shops with huge collections of Bisbee Blue turquoise. Wish I had bought some before they skyrocketed in popularity. But I was 15 and broke haha.

[@FeffurW]

I was looking for a guide how to identify a blue opal the other day, but I guess I have another stone to buy, thank you!

[@chantelmcskimming6633]

Thank you, great info.very clearly explained 😊

[@Phoenix684]

Grew up in the Navajo nation... turquoise is by far the prettiest gemstone of three. 😍😍

[@justahumanbean_]

I've never into geology but this random video is somehow caught my interest.. Very informative

[@TheXboxReviewer]

This video was published a year ago but has the energy of a video that was published in 2008.

[@DaroLinguiniJohnson]

Woah a cool video that i had no idea i'm interested in

[@imconfused5705]

Gotta love them secondary minerals

[@loriematthews6418]

At least you got right to the point. Thanks!

[@solostrings4056]

I would really like a video discussing Brazilian tourmaline, shorl, kyanite, and so called black kyanite. Not in separate videos btw. There’s a lot of “black kyanite” ive been seeing online, and it seems very unlikely that it is titanium coated or plated, rather than just shorl or Brazilian tourmaline. Thanks!

[@user-ip3pv2zx9w]

Very good.

[@Atmos_Glitch]

The algorithm has chosen this video

[@ejsuperstar]

As someone who does not care about turquoise in the slightest, great video! Very informative and enjoyable to watch, no idea why youtube recommended this to me, maybe cos of the mention of Fools Gold, as ive been watching a dnd campaign that goes by the same name

[@tomfitzsimmons6535]

I test turquoise three different ways, first it's checked for hardness, then treated with acetone to detect dyes, and finally with UV light to detect epoxies used to make composite turquoise. Epoxy glows.