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 Post subject: Please help me to ID is this seal a real nephrite jade?
PostPosted: Sun Apr 30, 2023 8:56 pm 
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Hello experts,
I have a clean seal that I got it from an auction. Is this a real nephrite jade?
Thank you for all your helps.


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 Post subject: Re: Please help me to ID is this seal a real nephrite jade?
PostPosted: Thu May 04, 2023 10:08 am 
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As with any other time someone comes to the forum to ask for an ID on a gemstone we will all say "We can never tell 100% from pictures alone" because we would have to have the piece to run our tests on it to actually positively identify any stone.

Based on the look I would say it might be but without bringing it to a local gemmologist that can physically test it then there's nothing else that we can really comment on for these types of questions.

I would recommend contacting a local jewellery store and asking if there's an appraiser/gemmologist in your area that you can bring it to. Best of luck though, it's a beautiful piece.

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 Post subject: Re: Please help me to ID is this seal a real nephrite jade?
PostPosted: Thu May 04, 2023 11:43 am 
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S. Rautiainen wrote:
As with any other time someone comes to the forum to ask for an ID on a gemstone we will all say "We can never tell 100% from pictures alone" because we would have to have the piece to run our tests on it to actually positively identify any stone.


As he said. Jade is one of those that I don't try to id even with it in the hand. I use a Raman on it. SO many things that it could be. Jade is one of them. So is serpentine. So is plastic, for that matter, though usually you can rule that out by weight.


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 Post subject: Re: Please help me to ID is this seal a real nephrite jade?
PostPosted: Thu May 04, 2023 2:03 pm 
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Looks like nephrite to me but without sounding too redundant, it needs to be tested in person by a qualified individual.


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 Post subject: Re: Please help me to ID is this seal a real nephrite jade?
PostPosted: Thu May 04, 2023 5:49 pm 
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I would say nephrite simply because so many sculptures were made from nephrite and more so than jade...but I am by no means any kind of authority ...


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 Post subject: Re: Please help me to ID is this seal a real nephrite jade?
PostPosted: Thu May 04, 2023 9:50 pm 
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Agree with many of the others.
Serpentine is commonly carved and appears like Nephrite Jade. So get it tested as suggested.

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 Post subject: Re: Please help me to ID is this seal a real nephrite jade?
PostPosted: Fri May 05, 2023 10:06 am 
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Thank you all,

I try to search and read many articles about nephrite jade. So I try to identify by myself with some aspects. This seal is 9cm tall x 7cm (to 7.2cm) on the square and weight 1206 gram. This seal was shipped from NANYANG, HENAN, CHINA. The seller listed it as "green Hetian Jade seal".

First, I used bright light to check and see many inclusions like tiny seaweed from grey to black all surfaces (see on new updated image). These inclusions doesn't attract the permanent magnet. It also have some streaks running through the surface . Besides, all the surfaces of seal don't change color under UV light.

Second, I did 4 times the test density (g/cm3) of seal with cool water, maybe my table is not exactly balance, therefore the results are a range from 3.10 to 3.38. base on the book "GEMs and precious stones" (Simon & Schust) 1986, page 244 about Nephrite they give density of this jade is: 2.9-3.4.

Lastly, testing the hardness. I just have a cheap Chinese hardness test device as on picture, don't have the professional device. I used it to test with purple amethyst/quartz (as a control sample) the hardness result is fairly stable at 7. For the seal, the hardness most of spots are 6, but some spots also give 7 hardness.

May I conclude this seal is nephrite jade?

Note: I would like to meet a local appraisal/gemologist, but I'm afraid of disturbing them for my private item. The price for certificate service for this seal size is also high.


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 Post subject: Re: Please help me to ID is this seal a real nephrite jade?
PostPosted: Mon May 15, 2023 1:42 pm 
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Assuming the tests were producing accurate results an SG of between 3.1 - 3.38 is a little high for nephrite. While "jade" is actually between 2.9 - 3.4 it's because the SG of Nephrite is usually between 2.8 - 3.1 and the Jadeite is between 3.3 - 3.4 and both nephrite and jadeite are considered "jade". (Gemmology Handbook for Gem-A)

Nephrite does have a hardness of 6.5 so some spots testing at 6 and others at 7 do make sense.

Ideally, you'd want to make sure the SG is accurate and test by the RI at bare minimum. If you have an accurate SG and RI then you should be able to identify it even without a Raman but the Raman would be the definitive answer.

Based on what you're describing and the test results (even if the SG is slightly off) I could see it being nephrite but you'd want to get the SG redone and at least a spot RI on the piece to confirm. Take a look in your area for a gemmologist appraiser and they would be able to help you identify it for certain. You won't be disturbing them, 95% of the appraisals are private items for people so it's par for the course.

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 Post subject: Re: Please help me to ID is this seal a real nephrite jade?
PostPosted: Mon May 15, 2023 2:39 pm 
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GIA Gem Reference Guide:
JADEITE
Specific Gravity 3.34 +.06/-.09
RI 1.666-1.680 +-.008, Spot 1.66
NEPHRITE
Specific Gravity 2.95 +.15/-..05
RI Spot 1.66

None of your tests would lead us to a conclusion.

Qualified Lab or Gemologist with the proper testing devices, anything other will all ways leave a dangling question in the back of ones mind.

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 Post subject: Re: Please help me to ID is this seal a real nephrite jade?
PostPosted: Mon May 15, 2023 6:16 pm 
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@S. Rautiainen, glhays:

Thank you, I also see my density test result is little higher than normal range, because I don't have standard tools and just use big normal plastic mug to test and my table is not perfect balance as a Laboratory. So I think the result must have disparity.

Recently, I have read about an article describing the dendritic pattern inclusions of nephrite jade from Guangxi province, China. I find that my seal also has a relatively similar pattern (not 100%), but clearly my seal has many grey dendritic inclusions like seaweed (see attached pic). I think it is also a remarkable sign to convince this seal is the natural jade. That article is here:

https://www.gia.edu/gems-gemology/fall- ... ince-china

Last week, I brought this seal to ask a local owner of jewelry shop. The owner said that it was a real jade item, but he can't define it belongs to nephrite or not. He advised me send this seal to GIA to get clearly certificate what kind of jade and he also gave a basic estimate valuation for me.

For the RI test, I don't have this instrument. I'm thinking about the local jewelry owner advice should I send this seal to GIA service for identifying (price $330 + not include tax + shipping) or use money to buy a RI instrument to test by myself and for many cases later? :)

Can you introduce me the good RI instrument with reasonable price? and how to test RI with big sample like this seal?


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 Post subject: Re: Please help me to ID is this seal a real nephrite jade?
PostPosted: Mon May 15, 2023 9:06 pm 
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Dendritic formations are common in many materials, many agates have them.

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 Post subject: Re: Please help me to ID is this seal a real nephrite jade?
PostPosted: Mon May 15, 2023 11:20 pm 
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glhays wrote:
Dendritic formations are common in many materials, many agates have them.

Yes bro, but it is very hard/rare to see the green agates having the texture like this seal. Usually, most of green agates have many clearly white striations/lines on the surface. Agates have lower density around 2.66 than jade, it doesn't heavy like this seal.

For the color (only color, I don't mean my seal has too big valuation), I think my seal color has a relatively similar with the below imperial seal:
https://www.bonhams.com/auction/22882/l ... l-jiaqing/

Today, I have repeated 5 times density test this seal using another table with more balance. The result is a range from 3.068 to 3.19.


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 Post subject: Re: Please help me to ID is this seal a real nephrite jade?
PostPosted: Wed May 17, 2023 2:04 pm 
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At this point, more pictures won't help, the main thing to do is bring it to a local gemmologist appraiser or send it to GIA. The less expensive option would be bring it to a gemmologist and they would likely be able to identify it quickly enough as they would be able to run a test to find the RI or they would have a Raman which would identify it quickly.

Best of luck in trying to identify the piece, it's certainly a nice one.

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 Post subject: Re: Please help me to ID is this seal a real nephrite jade?
PostPosted: Wed May 17, 2023 9:13 pm 
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Nanmu86 wrote:
glhays wrote:
Dendritic formations are common in many materials, many agates have them.

Yes bro, but it is very hard/rare to see the green agates having the texture like this seal. Usually, most of green agates have many clearly white striations/lines on the surface. Agates have lower density around 2.66 than jade, it doesn't heavy like this seal.

For the color (only color, I don't mean my seal has too big valuation), I think my seal color has a relatively similar with the below imperial seal:
https://www.bonhams.com/auction/22882/l ... l-jiaqing/

Today, I have repeated 5 times density test this seal using another table with more balance. The result is a range from 3.068 to 3.19.

No need in getting hasty, was just stating a fact. I was not implying this piece is agate. As you should see that your test results can not come to a conclusive id. My money is on Nephrite.

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 Post subject: Re: Please help me to ID is this seal a real nephrite jade?
PostPosted: Thu May 18, 2023 11:51 am 
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@ S. Rautiainen
Thank you for your suggestions. I'm still thinking to use GIA service or not. I'm also searching to buy a refractometer to do the RI test by myself and for some later collective cases. The local gemmologist just help by looking quick and use light & UV to check and reply, if I want to do more detail tests, it usually cost a fee, not free. So I don't dare to bother them.

@ glhays
Bro, I'm no need to be hasty. Honestly, your state was not a fact, it is just a part of a fact. A fact in here (agate or nephrite jade) must include some/many aspects (color, texture, inclusion, vein/line on the surface, fracture, hardness, SG, RI,..etc.)

Generally, in this "Beginners Only!" section, a newbie (like me) only posted some strange mineral/stone pictures to ask for help identifying an item with the hope that many experienced experts will give the suitable/proper suggestions about an item. Because the newbie can't do the right/scientific tests or have proper instruments to do tests.

That is my opinion. I'm sorry if it make you don't be happy. Our debatement should end in here. Thank you!


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