January 24 Through February 4—TUCSON, ARIZONA: Annual show
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Thu Mar 28, 2024 5:49 pm

All times are UTC - 4 hours




Post new topic Reply to topic  [ 8 posts ] 
Author Message
 Post subject: Umbalite garnet... questions!
PostPosted: Fri May 13, 2016 4:04 am 
Offline
Valued Contributor
User avatar

Joined: Mon Apr 06, 2015 10:37 am
Posts: 104
Location: Latina- Rome
Dear friends,
I would like to receive some info about Umbalite garnet...
It looks very similar to a good quality Rhodolite at first look, but I read that it has a different chemical composition.
As a matter of fact, it is reported that umbalite is a mixture of pyrope and spess
http://www.gemdat.org/gem-27164.html
It is mined in one single location: the Umba river.
Thus, might it be considered a rarer and more expensive kind of garnet than rhodolite?
I found that its price is around 100/150 dollar/carat on the web.
But on Gemval and on my edition of The GemGuide (2013), the price per carat of Umbalite is not reported.
Does anybody have an idea about the value?
Thanks!!!!


Top
 Profile  
Reply with quote  
 Post subject: Re: Umbalite garnet... questions!
PostPosted: Fri May 13, 2016 12:54 pm 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 21602
Location: San Francisco
Gemval is not a reliable pricing source.

There is no blue book on gem pricing. One has to define the market in which something is valued.
(Actually even the Blue Book for cars defines the market in which they value the vehicle.)

That being said, I would suggest starting with this article from the GIA,
Vanadium- and Chromium-Bearing Pink Pyrope Garnet: Characterization and Quantitative Colorimetric Analysis


Top
 Profile  
Reply with quote  
 Post subject: Re: Umbalite garnet... questions!
PostPosted: Fri May 13, 2016 1:32 pm 
Offline
Valued Contributor
User avatar

Joined: Mon Apr 06, 2015 10:37 am
Posts: 104
Location: Latina- Rome
@Barbra
Thank You for the valuable suggestions!!!


Top
 Profile  
Reply with quote  
 Post subject: Re: Umbalite garnet... questions!
PostPosted: Sat May 14, 2016 4:45 am 
Offline
Gemology Online Veteran
User avatar

Joined: Sat May 22, 2010 2:51 am
Posts: 755
Location: South Africa
Barbra Voltaire wrote:
Gemval is not a reliable pricing source.

Barbara, would you care to elaborate? I am not challenging your opinion, on the contrary I respect your industry knowledge, but it would be helpful to know why you find it unreliable. My understanding is that it is based on surveyed internet retail prices, excluding extremes, so what is wrong with it? Is there a systematic bias in Gemval's pricing that one could compensate for?


Top
 Profile  
Reply with quote  
 Post subject: Re: Umbalite garnet... questions!
PostPosted: Sat May 14, 2016 12:24 pm 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 21602
Location: San Francisco
let's take apatite for example:
http://www.gemval.com/chart.php?type=21

eBay
Image

Gem Select

A higher end offering:
AJS Gems

A lower end offering
Gem Rock Auctions

So, where are we finding the prices reflected in GemValue?
They define the market as "Apatite: average retail prices, May 2016".
All the stones above are available in a retail online market.
So where is this "retail market" used for GemValue?


Top
 Profile  
Reply with quote  
 Post subject: Re: Umbalite garnet... questions!
PostPosted: Sat May 14, 2016 1:50 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Sat May 22, 2010 2:51 am
Posts: 755
Location: South Africa
Barbra Voltaire wrote:
So where is this "retail market" used for GemValue?

They seem to be listed here. http://www.gemval.com/resources.php
Are these all expensive, high-end outlets that don't really represent the global market? I take the point that the market is different in different geographies, so perhaps Gemval represents only the top-end US market. But Gemval looks conveniently user-friendly for a rough-and-ready price guide, so it would be nice to know if there is a consistent factor by which one could adjust Gemval values to be more realistic. Or are they just all over the place?


Top
 Profile  
Reply with quote  
 Post subject: Re: Umbalite garnet... questions!
PostPosted: Sat May 14, 2016 2:20 pm 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 21602
Location: San Francisco
If I am looking to value a gem, the first thing I would do (after determining the quality of the gem from a professional standpoint: color, clarity, cut quality, treatment,) is to define exactly how and where the stone is to be replaced.
- the store where the client purchased it?
-online through, let's say through AJS
-Home Shopping Network?

Secondly, simply do some research in the defined market and list those sources on my documentation,

Even if someone brings something in that was a gift or an inheritance, the first thing I discuss is defining a market for replacement.

Yes, it involves a couple extra steps, but that's what folks pay me to do. :D

There is really no Blue Book on Gem Pricing......shortcuts perhaps. Think about it for a second. If you were doing broad research on any other topic and your sample size was 13, would you consider the findings reliable?

There is a caveat. If indeed, you are defining the replacement market to be precisely those 13 options, fair enough. But, I would still actually contact those sources personally and individually, describe what I need a value on through my eyes and get actual quotes.


Top
 Profile  
Reply with quote  
 Post subject: Re: Umbalite garnet... questions!
PostPosted: Wed Jan 30, 2019 10:49 am 
Offline
Platinum Member

Joined: Tue Jun 03, 2008 4:40 pm
Posts: 2667
Location: South Dakota
Barbra Voltaire wrote:
If I am looking to value a gem, the first thing I would do (after determining the quality of the gem from a professional standpoint: color, clarity, cut quality, treatment,) is to define exactly how and where the stone is to be replaced.
- the store where the client purchased it?
-online through, let's say through AJS
-Home Shopping Network?

Secondly, simply do some research in the defined market and list those sources on my documentation,

Even if someone brings something in that was a gift or an inheritance, the first thing I discuss is defining a market for replacement.

Yes, it involves a couple extra steps, but that's what folks pay me to do. :D

There is really no Blue Book on Gem Pricing......shortcuts perhaps. Think about it for a second. If you were doing broad research on any other topic and your sample size was 13, would you consider the findings reliable?

There is a caveat. If indeed, you are defining the replacement market to be precisely those 13 options, fair enough. But, I would still actually contact those sources personally and individually, describe what I need a value on through my eyes and get actual quotes.


I was doing some reading on pink garnets, when I came across these couple post from Barbra, which I thought were fantastic!! So, that means I had to at least stop for second to say ....great post!!!!!

_________________
MrAmethystguy ~ Some jokes just fluorite over my head!


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 8 posts ] 

All times are UTC - 4 hours


Who is online

Users browsing this forum: No registered users and 29 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Gemology Style ported to phpBB3 by Christian Bullock