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 Post subject: gemval historical value?
PostPosted: Sun Aug 19, 2007 12:19 pm 
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i just looked up gemval's history of chrome tourmaline prices,it says the basis weight for the values is 16ct!!! does such a sized chrome tourmaline even exist?!! seems like a strange basis weight as that would be an incredibly rare weight. am i missing something? :smt017

http://gemval.com/default.aspx?fuseaction=history


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PostPosted: Sun Aug 19, 2007 12:29 pm 
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Sadly, I don't think I've ever agreed with the blind values ascribed on gemvalue.com
GemValue would not be on my short list of recommended sites for gem valuation.


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 Post subject: Re: gemval historical value?
PostPosted: Fri Jun 25, 2010 12:07 pm 
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Hi and welcome to the forum,

Ouisri wrote:
Try geo.utexas.edu, you will get real information..


i don't see where the Department of geological science of Jackson school of geosciences actually gives the "real information" about the value of the chrome tourmaline posted, please elaborate, i'm missing something here.

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alberto

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 Post subject: Re: gemval historical value?
PostPosted: Fri Jun 25, 2010 10:10 pm 
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I followed the link to find they they have some information from a Gemology Class they offer here:
http://www.geo.utexas.edu/courses/347k/ ... _frame.htm

And all the gems described have a pricing section.
I clicked on tourmaline and at the bottom of the page and saw there was some pricing listed.

Prices seem to be based on 1989 values, but do not seem unreasonable in 2010.


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 Post subject: Re: gemval historical value?
PostPosted: Sun Dec 26, 2010 4:40 pm 
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I always thought the prices seemed to be high for pricing loose stones.
We still use it for reference.
my .02 cents


Joey


loose gemstones


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 Post subject: Re:
PostPosted: Sun Jul 27, 2014 3:15 am 
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Barbra Voltaire wrote:
Sadly, I don't think I've ever agreed with the blind values ascribed on gemvalue.com
GemValue would not be on my short list of recommended sites for gem valuation.

Yes, I agree that the values calculated by gemvalue.com seem to be a bit high: so which are the alternatives to it?


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 Post subject: Re: Re:
PostPosted: Sun Jul 27, 2014 11:51 am 
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Australian wrote:
Yes, I agree that the values calculated by gemvalue.com seem to be a bit high: so which are the alternatives to it?


have a look here: http://gemguide.com/

ciao
alberto

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 Post subject: Re: gemval historical value?
PostPosted: Mon Jul 28, 2014 12:40 am 
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Thank you, Alberto. You must use the website you recommend and also be member of Gem World and also have their software. Would you mind running through your software this imperial topaz? Here is the sequence of entries into Gemval I have used:
1 - topaz
2 - 2.92 ct
3 - 033 - medium light orange, etc
4 - VVS
5 - good (cut)
6 - pear
Value: USD 622.29

I have done some back checking of Gemval, ie I chose gemstones from the website of one of their partners and entered the characteristics from it into Gemval. Strangely enough, the output from Gemval was a lot lower than the listed price. This was unexpected. I checked gemstones from a different range of prices and weights.


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 Post subject: Re: gemval historical value?
PostPosted: Mon Jul 28, 2014 12:53 pm 
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I'm not a subscriber of the gemguide. You asked for alternatives to Gemval, i provide for it.
ciao
alberto

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 Post subject: Re: gemval historical value?
PostPosted: Mon Jul 28, 2014 1:12 pm 
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Here is the issue as I see it.
How can any software (or professional, for that matter) put a value on a gem without knowing the accuracy of the information supplied?

Imperial Topaz? Says who?
What is the level of treatment this stone has undergone? And how was that determined?
Color stable? How do you know?
Good cut? Says who?
Value? Wholesale? Retail? Online? Online vendor or auction? In what part of the world? Under what conditions?

I don't mean to be cross, but if you were qualified to answer all the questions above, you wouldn't be using a program like gemval to determine a value. :wink:


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 Post subject: Re: gemval historical value?
PostPosted: Mon Jul 28, 2014 1:20 pm 
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for not to speak about the likely more important question: where??
From your nickname you seem to be very far from my market (Italy) , how could i give you an advice suitable for my market which can work for yours too??.... :wink:

ciao
alberto

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 Post subject: Re: gemval historical value?
PostPosted: Mon Jul 28, 2014 8:47 pm 
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Thank you Barbra and Alberto for your knowledgeable comments.

Yes, I do live in Australia, but was born and grew up in Italy.

From your comments, Barbra, I understand that the valuation of a gemstone is very complex. So how can a valuer practice his/her trade when he is asked to assess a gem (or a piece of jewellery with a gem or more), but the customer can only provide information on the item as received by the seller? The seller is most likely going to be unknown to the valuer. People rarely buy from a registered gemmologist. They mostly do from a jeweller who is very unlikely to be a gemmologist. Alternatively they can buy from a dealer at gem show or on the internet.

If I have understood your comments correctly, the price of a gem depends upon the market and the seller armed with marketing skills ranging from simple (like name, weight, size), to more knowledgeable (eg clarity) to sweet talking the customer to conning him/her.

Back to the original question, I won a 9 ct gold ring at a gem show here earlier this year. It has an Australian yellow sapphire (0.3 ct from size) and two red tourmalines (0.35 ct each). The certificate was issued under the title of "valuation for retail replacement". The value was estimated to be A$800 as of 13 Nov 2013. Then there are two caveats:
1) stones assessed in setting, measurements and weights estimated only;
2) valued to replace at a traditional "bricks and mortar" establishment.
The valuer is officially registered and well known here, one of the largest cities in Australia.
What type of credibility should I give to this valuation?

On a broader side, how many times can a client provide all the information you are mentioning so that you provide an unambiguous valuation?

If I wish to sell gemstones locally, then my best bet is to see the prices of the competition (dealers at gem shows, although I am not one of them) and pitch my prices slightly below it. I can also go to a few local jewelleries and see what pricing I can get out of them considering that they will only sell stones already set. I may look at prices on the internet. Then I can try to get a customer, describe the stone as factually as I can (eg weight, cut type, size, mineral species) and state a price. If the buyer accepts it, I have a sale. If the buyer haggles, I may come down in price as a function of my purchase price and willingness to sell. It is up to the buyer to like the stone regardless of any other parameters, eg clarity, quality of cutting, etc. As a selling pitch I may add: "Does it look wonderful"? I would consider anything else like hard selling which I believe to be questionable.

Through this exchange of information I like to find a way to be able to sell the few gemstones I have in an honest way.


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 Post subject: Re: gemval historical value?
PostPosted: Mon Jul 28, 2014 10:31 pm 
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Quote:
So how can a valuer practice his/her trade when he is asked to assess a gem (or a piece of jewellery with a gem or more), but the customer can only provide information on the item as received by the seller? The seller is most likely going to be unknown to the valuer. People rarely buy from a registered gemmologist. They mostly do from a jeweller who is very unlikely to be a gemmologist. Alternatively they can buy from a dealer at gem show or on the internet.


A customer needs to educate themselves before making a purchase. Not the least of which is researching whether or not a potential vendor is reliable.

For a professional appraiser, the first thing which needs to be determined is the market in which the valuation is based.
Then, one must have the piece in front of them to access a value. Optically test an unknown to verify its identity; check it with the microscope to look for inclusions or features which may effect value; check quality of faceting: light return vs. leakage, facet meets, etc. Then, research, research, research. :D


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 Post subject: Re: gemval historical value?
PostPosted: Mon Jul 28, 2014 11:15 pm 
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I totally agree about customers educating themselves. However, this happens very rarely in the real world. Customers buy gemstones because they like them or, if they are into alternative lifestyle, the stones are related to the month of birth, a metaphysical healing property, etc. In my opinion as long as I can provide information from a reliable source about the stone, then I feel happy as a seller. Then I will pitch the price according to the market. In my opinion for the average person who buys a stone once or twice a year at a gem show, it is very hard to assess the reliability of a vendor.

I like your comment about the market and how it is related to the value of a stone.

I also agree that, once you have tested the unknown gemstone for a client according to a series of tests, then you may need to do more research. However, how far do you take your research to insure you are not overcharging your client?

Regarding the definition of the imperial topaz, I thought it was related to topaz mined in Brazil and displaying a full range of colours from pale orange to red. Of course, a topaz of similar colour and mineralogy characteristics, but mined in another part of the world can also be considered imperial. As you mentioned before, the nomenclature for coloured gemstones is not officially sanctioned like it is for diamonds.

Thank you for your comments.


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 Post subject: Re: gemval historical value?
PostPosted: Tue Jul 29, 2014 2:06 am 
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Australian wrote:
Regarding the definition of the imperial topaz, I thought it was related to topaz mined in Brazil and displaying a full range of colours from pale orange to red. Of course, a topaz of similar colour and mineralogy characteristics, but mined in another part of the world can also be considered imperial.

Imperial topaz is one of those oddities that takes a lot of looking at to get a feel for. It's a very different beast from the more common and often large blocky topaz which come out of igneous pegmatites (think Colorado, Pakistan, other parts of Brazil) or rhyolitic topaz (Mexico, Utah), even though you can also get varying reddish-orange, peaches and red-browns out of those too. The crystal form of topaz from these particular Brazilian deposits is very different and distinct, and is only shared by a couple of other deposits with similar geology (Sanarka Russia, Karengarenge Village Zambia, Katlang Pakistan).
Once you've made that separation, then you have to deal with the color. The stones which have the real imperial range of colors are chromium-bearing. Chromium causes pinks, magentas, purples and 'reds' (really, the red is red-magenta but who's keeping score). That chromium along with radiation-induced color centers give them that intense red-orange color to varying degrees, and in the Brazilian stones this is stable. Those colors are often zoned and blended within one crystal, and when you add the pleochroism on top of that you get a wide range of possible looks even within that relatively limited part of the spectrum. How the heck are you supposed to quantify that into a drop-down menu?
Some people would want to limit the use of the term exclusively to Brazilian stones--at this point it hardly matters, because of the very limited availability of similar material from other parts of the world. Natural oranges come from Zambia, but that's a very limited deposit and most of them (all of them?) seem to be more valuable as specimens (and the ones I've seen in person seemed to get a lot of their color from iron oxide inclusions anyway). Pinks from Pakistan can be irradiated to produce intense orange-red stones (different from other brown irradiated stones from there) but the color fades to a pale orange, yellow or colorless and it's hard to get even that stuff. Sanarka material is so vanishingly rare on the market these days that I would feel lucky to see any, ever. Some day they'll find another serious deposit, there will be some fighting and consternation and the Brazil-only advocates will lose (but probably never stop complaining).

What I'm saying is, Imperial topaz is a complicated term for a kinda screwy gem, and you're going to get different opinions on where the line must be drawn. On the one hand there are the stones which nobody would disagree with, the finest and most intense high-end Brazilian beauties. On the other hand is how many eBay sellers use the term, for any stone with any sort of orange, yellow or brown component to its color, natural or not, photostable or not. Some of those opinions matter a lot more than others, but there's not a single, hard and fast definition.

So, you can see that even a high-profile term like Imperial Topaz is subjective and a touch arbitrary under the surface. The key point is that so is pricing them. Some gem varieties are obviously worth more than others, some colors are worth more than others, better cut stones are worth more than poorly cut stones, but at the end of the day each one is an individual. Ultimately the number you usually want for an item's "worth" is what you can get someone to pay for it if you're a seller, or what you'd be willing and able to spend on it (or not regret spending on it, or regret not spending on it) as a buyer, or what it would cost to replace it as an owner. But none of those are singular values, because sellers and buyers are also individuals. One person is more persuasive than another, one is more chintzy than another, one finds more appeal in that particular piece than another, one stone or seller has a better story than another, etc. That's why a program like this is never fully predictive, and really never can be. Prices are more like electron orbitals than fixed points--you have an idea of where it is most probable to be but not the exact position. On some things it will probably give you a very reasonable estimate, and on others no doubt it will be outrageous, but you can be sure that someone somewhere has probably spent both more and less on a similar stone.


Wow that's a huge wall of text. Sorry about that, I'm on benadryl.

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