National Shutdowns have put the lid on most shows.
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Sun Aug 09, 2020 7:21 pm

All times are UTC - 4 hours




Post new topic Reply to topic  [ 9 posts ] 
Author Message
 Post subject: Fracture filled garnet?
PostPosted: Wed Mar 02, 2011 11:52 am 
Offline
Established Member
User avatar

Joined: Fri Jan 21, 2011 11:04 am
Posts: 18
Location: Denmark
I have some garnet beads from several different sources, all showing the same suspiciously coloured fractures. I took some photos:
Image
Image
The original images are 100x, but I reduced the size in photoshop a bit.

Both beads show this orange-brown grainy substance in the fractures. On some stones the garnet is too dark to the treatment being visible to the naked eye, but after noticing it in the microscope It's not that hard to miss in the lighter red garnets.

So here's my questions:
What is this substance? Any ideas?
How durable is this kind of treatment? (An added unknown here is how long the people I bought these from have had them)
If I disclose the beads as treated/fracture filled would it be OK to use them in jewellery?
Should I just add the garnets to my ever-growing collection of "pretty but useless gravel" that adorns my potted plants?

As long as I have no idea if they are suddenly going to fall apart in a couple years, those beads aren't going anywhere. I'd rather take the loss than have dissatisfied customers.


Top
 Profile  
Reply with quote  
 Post subject: Re: Fracture filled garnet?
PostPosted: Wed Mar 02, 2011 12:46 pm 
Offline
Gold Member
User avatar

Joined: Wed Nov 15, 2006 9:44 pm
Posts: 1076
Location: Washington State
My guess, from many thousands of miles away, is that those fractures have naturally occurring iron oxide stains in the fractures. Many minerals evolve in environments which have high iron contents, and that iron will oxidize and flow, in combination with groundwater, into fractures in the surrounding minerals, leaving small deposits. Many of the schists and gneisses locally have garnets which have this feature. Most of the garnets having been so fractured and stained over time that they look like little rust balls.

I also can't imagine anyone going to the trouble of fracture filling inexpensive garnets, but stranger things have happened. You could always send one of the suspect beads to a lab with some high tech equipment, but the cost for testing may be more than the beads are worth.

_________________
Michael E.


Top
 Profile  
Reply with quote  
 Post subject: Re: Fracture filled garnet?
PostPosted: Wed Mar 02, 2011 2:11 pm 
Offline
Site Admin

Joined: Thu Jan 05, 2006 4:27 pm
Posts: 1750
Quote:
I also can't imagine anyone going to the trouble of fracture filling inexpensive garnets, but stranger things have happened. You could always send one of the suspect beads to a lab with some high tech equipment, but the cost for testing may be more than the beads are worth.


I haven't seen any for myself but swishman (Jamie) has posted some pretty convincing pics that garnets are indeed being fracture filled. try pickling some of the beads in acid (even lemon juice might work).

You really need to send em to a gemmologist or a lab to be sure though


Top
 Profile  
Reply with quote  
 Post subject: Re: Fracture filled garnet?
PostPosted: Wed Mar 02, 2011 5:21 pm 
Offline
Established Member
User avatar

Joined: Fri Jan 21, 2011 11:04 am
Posts: 18
Location: Denmark
Frank wrote:
I haven't seen any for myself but swishman (Jamie) has posted some pretty convincing pics that garnets are indeed being fracture filled. try pickling some of the beads in acid (even lemon juice might work).

You really need to send em to a gemmologist or a lab to be sure though

The topic you are referring to was the reason I put the garnets under the microscope. I read all 8 pages of it some days ago and went "Oh :shock: - I better go check all my garnets!"

Pickling some seems like a good idea. How long should I leave them in there? Would pickling draw out any natural iron oxide, if this is what it is?

The possibility of this substance being natural somehow seems right to me, for three reasons. If I was fracture filling some stones - even cheap ones - I'd use a substance that weren't so easily spotted. The colour difference is quite obvious once you notice it. Also, I had another look and not all the coloured fractures reach the surface of the stones, so how could a filling agent get in there? Last; some of the beads (top image) are from the Czech Republic, and I don't remember it being mentioned as one of the countries routinely doing fracture filling. Even so, natural or not, I don't know enough to judge if the beads are strong enough to use. The fractures must make them weaker, though so far they have withstood being faceted and drilled (and mailed half-way across the world and back). May it's good enough if I just sort out the ones that look a bit rust-ballish and disclose the fact that the beads have flaws.:?

These beads are too inexpensive for it to be meaningful to pay for a test; I have 3 different bead lots worth a total of $30. What's most important to me is not disappointing someone buying my jewellery. If in the end I still have doubts about the durability of the beads, I'll just make something fun and wear it myself.


Top
 Profile  
Reply with quote  
 Post subject: Re: Fracture filled garnet?
PostPosted: Tue Mar 15, 2011 6:19 pm 
Offline
Established Member
User avatar

Joined: Fri Jan 21, 2011 11:04 am
Posts: 18
Location: Denmark
Well, I pickled a couple of beads as Frank suggested. I let them sit in vinegar for a week, and especially one came out looking rather bad. I took some shots with my digital camera directly through the eyepiece of the microscope. The magnification on the scope was 50x. This is from the end of the bead, you can see part of the drill hole in the bottom right corner of the two top photos. It looks to me like a wedge-shaped flaw in the garnet has been filled with a colourless substance (glass?) and between this and the garnet are the thin layer of orange-brown something (resin?, glue?) that can be seen in my first post. This last bit is not as obvious in the photos as I saw it in real life, but I've done my best (took 70 photos to get these).
After seeing this I've decided against using the beads for the jewellery that I sell. I've not yet decided whether I should contact the person who sold me these, though. I'd like to hear what someone else thinks first. Does it look like I'm right about this being glass filled garnet?
Image
And in a different light:
Image
As seen form the side:
Image


Top
 Profile  
Reply with quote  
 Post subject: Re: Fracture filled garnet?
PostPosted: Tue Mar 15, 2011 9:19 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Sat Jul 11, 2009 10:29 am
Posts: 928
Location: USA
I haven't finished Part II of my research yet due to my health, but I can tell you much of it is simple resins/epoxies. There are various materials being used but I have recreated the exact method, or at least the exact results, using Opticon. Unless you subject the filled stones to high heat, acid or other type chemicals, or ultrasonic cleaning they do seem to hold up OK as I have been testing one now since I wrote the original article and it shows no signs of any deterioration yet, but then again Opticon has been used by many Aussie Opal cutters for decades, hehe.

It seems the most commonly treated garnets are the orangish colored hessonites, and going along side my own testing, they respond the best to the treatment for whatever reason. Many red ones show no real difference other then some better surface appearance.

The reason they are bothering to do this on garnets I am guessing is because the results are very much improved from the original and the fact that it costs a few cents to treat 100 stones or even more! And it can be done by anyone with a heat source even if just a coffee pot heater! Spend .001 cent per stone and sell on Ebay for .99 cents+ and the $5 or so the typically make off of shipping, it adds up quickly!

Keep in mind people are now diffusing garnets as well if you check out Ted's website. :/
http://themelis.com/Gem-new.html

_________________
http://www.gemaddicts.com <--- My Website
http://www.gemsbyjennifer.com/store <---- Wifey's Store
http://www.flickr.com/photos/digitaldevo <--- My Portfolio


Top
 Profile  
Reply with quote  
 Post subject: Re: Fracture filled garnet?
PostPosted: Thu Mar 17, 2011 8:59 pm 
Offline
Gemology Online Royal Princess

Joined: Mon Oct 17, 2005 10:56 am
Posts: 6462
Location: The frozen north prairie :-/
And Ted is teaching them to diffuse spinel now, as well :smt022

He had both diffused garnets and spinels for sale in Tucson.

_________________
IIJA Registered Gemologist
GIA Graduate Gemologist


Top
 Profile  
Reply with quote  
 Post subject: Re: Fracture filled garnet?
PostPosted: Sat Mar 19, 2011 12:55 am 
Offline
Established Member
User avatar

Joined: Fri Jan 21, 2011 11:04 am
Posts: 18
Location: Denmark
Hello Swishman, and thank you for sharing your findings.
Swishman wrote:
Unless you subject the filled stones to high heat, acid or other type chemicals, or ultrasonic cleaning they do seem to hold up OK as I have been testing one now since I wrote the original article and it shows no signs of any deterioration yet

What worried me most - and still does - after reading the 'Garnet inclusions' thread was that you mentioned some stones where the filling was degraded significantly after a couple years:
Quote:
We got a couple Alexandrites from one on Ebay about a year ago, reputable to many, so never bothered to check them yet as they are Jen's collection and not for sale anyways, but when packing for the move we noticed the filler material has already started to break down on them and what were once clear/clean stones to the eye now have the color flashes and fissures and all kinds of things showing up to the naked eye! Same thing happened to a tsavorite from a reputable seller!
I have no idea how long ago my garnet beads were treated or with what since it was (obviously) not disclosed, and it's likely that the seller didn't know about it. They can very well have been in the sellers possession for years before I bought them.

I think the lack of disclosure itself is also a reason for my worry - I mean, other types of treatments are widely accepted as for example stabilization of turquoise, and when a treatment is properly disclosed and explained I usually have no problem with it. But when information is being withheld I can't help but think that it must be because the treatment in question is somehow not really a good thing - that maybe the natural stone started out as unusable, and that maybe the treatment is not durable or stable enough to keep the stone from reverting to being unusable again. So I prefer to err on the side of caution and not resell stones that only might hold up OK, as you say, because they also may not and then I'll be the one who loses credibility.


Top
 Profile  
Reply with quote  
 Post subject: Re: Fracture filled garnet?
PostPosted: Wed Mar 23, 2011 12:05 am 
Offline
Gemology Online Veteran
User avatar

Joined: Sat Jul 11, 2009 10:29 am
Posts: 928
Location: USA
The alex was not the same as the garnets I don't believe. I have had a few of these garnets now for a quite a few years and no degradation yet. The Alex was something different, I am thinking maybe an oil or the like as there was a very very slight discoloration to the foam in the gem jar. They were our own fault for not checking them, lol, but trust me, everything, even for Jen's collection, gets tested after that, lol! Luckily it was not an expensive ordeal as they were not super great quality and only had slight color change. Just something she wanted to have, lol.

But the Garnets, at least the ones I have, seem to be holding up fine. I will have more info on all of it when finally get done Part II.

_________________
http://www.gemaddicts.com <--- My Website
http://www.gemsbyjennifer.com/store <---- Wifey's Store
http://www.flickr.com/photos/digitaldevo <--- My Portfolio


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 9 posts ] 

All times are UTC - 4 hours


Who is online

Users browsing this forum: No registered users and 2 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