Color Stone Removal Process Question

[ilzho]

Hello:

I apologize in advance if this is not posted in the right area.

I have a question about the color stone removal process. I received my diamonds/colored stones back from a refiner.

My czs are frosted which is great and the diamonds are fine (Some are have a hard milky glaze), but the color stones have a hard glaze attached to them.
I am not sure if they are partial melted or if some type of acid solution has attached to them and harden.

I'm just trying to understand the process, during the color stone removal process.

If you have any insight I would greatly appreciate it.

 

[nickvc]

The actual stone removal is done in Aqua Regia which can damage some of the softer coloured stones such as opals, emeralds and tanzanites but the harder stones such as rubies and sapphires should be fine, the use then of hydrofluoric to frost the czs will also attack the surface of other stones. If your doing big volumes I doubt the refiner has the time to sort them out before the hydrofluoric treatment so you could ask for them back and sort them yourself and then send the white stones back to be frosted. I have buyers for broken diamonds and coloured stones if of good size and quality and they are rising in price rapidly.

 

[ilzho]

Hi:

Here are some pictures to help see the shiny hard stuff attached to most stones.

 

[nickvc]

Looking quickly at your pictures I'd say most of the coloured stones are synthetic or czs the large square stone could be ruby and I think you have some sapphires in there, the pale green stones could be emerald but the acids leeched the oils out, they can be re oiled with almond oil and the colour restored to some extent. The only way to know what you have is experience and there are no testers to tell between created and real gemstones but I would say any really badly attacked stones are rubbish now if not before hand, hydrofluoric takes few prisoners it's nasty stuff!

 

[ilzho]

Oh yeah there are plenty of syn sapphires, etc... Now I would like to think that the hydrofluoric acid only destroys the syntheitcs

I'm just trying to figure out if the Hydrofluoric acid caused the the glaze and etching. I mean everything you see here is going into the trash. The glaze or what ever it is cannot be removed and has destroyed the facets.

I just want to know so I can tell the refiner what to do or what not to do next time.

Thoughts?

 

[Dan Dement]

No, HF has no effect on either Syn Sapphires & Rubies (corundum) . Understand, Both are REAL only one is manmade. Most of the stones in the picture are syn. Corundum. the graining in the Syn. are curved.

Dan

 

[ilzho]

So does anyone know why these stones have that hard glaze or whatever it is on these stones?

 

[4metals]

Difficult to say from the pIctures but a white crust or glaze can come from crusted dried silver chloride that was not completely removed before drying. Try soaking in a concentrated ammonia solution which will dissolve the chloride. It may take a while to dissolve dry crusted chloride so give it an overnight soak. If its gone in the morning you know the answer. I agree that all of the stones should not be etched in the HF, ask the refiner to ship back all of the stones without etching and separate the colored stones manually and etch the diamonds / cz's yourself it is not difficult. I do not know what stones are damaged by HF and which are not because I always preferred to sort out the colored stones before treatment. It isn't that hard to do, the diamonds are almost always the smaller stones so the majority of the separation is quickly done with a diamond sizing screen.

 

[glondor]

I would not throw them in the trash. I would just put them in a jar on the shelf for a while. You never know when you will find use for colourful semi precious stones.

 

[Palladium]

Could that be from Sodium Thio ?

 

[ilzho]

4metals: If I try soaking them in ammonia, do I need a particular strength or just get it over the counter and see if it works?

glondor: These stones are not worth saving unless this hard glaze can be removed. I do save everything, but the glaze is like superglue. I cannot get it off, it gives the stone a wet look and its frustrating, lol.

 

[Chiptech81]

Just wondering from just the pictures what is it people see to say they are synthetic stones?
Its a shame they got damaged in solution as i could have made a use for them.

 

[ilzho]

Well it's in the 2nd/3rd picture where you can see some of the bigger stones that are in men's rings, they are usually syn corundum rubies/sapphire, others as well.
As a gemologist, I can tell even with the this crappy coating on them. I just wish I knew what destroyed them.

 

[ilzho]

Well I am soaking some in ammonia, so we will see what happens.

 

[ilzho]

Well, I soaked some in pure ammonia and no improvement. It's still on them.