Testing inexpensive stones

[innerkitten]

What if you want to find out if a stone that only cost you forty dollars is genuine? I mean it seems crazy to spend more than the price of the actual stone to send it to a lab. Know what I mean? Any thoughts?

 

[Cave Keeper]

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On 7/24/2004 4:13:05 PM innerkitten wrote:

What if you want to find out if a stone that only cost you forty dollars is genuine?
:
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If it is cheap enough, I'd consider scratching something softer (also, meaning cheaper) with it to verify its hardness is at least as expected. Or scratch it with something softer to confirm it's harder. You might need to own a set of stones to use for testing.

Another way is to test its specific gravity. You'll need a weighing device plus a measuring cylinder. Plus the stone needs to be loose.

Still another way is to examine its crystalline structure with either a 15x or 20x (preferred) loupe or a 30x microscope. And also to look for bubbles, glassy curvature or lack of flaws. You might need to own a set of stones to become familiar with their crystalline structure, plus buy a loupe or microscope. Plus a book or two which includes adequate information on the crystalline structure of the stone you're interested in.

Curiosity costs money. But those are one-time costs.

 

[Michael_E]

innerkitten,
It all depends on what you think you've got. If you've acquired a stone that you believe may be worth a lot more than what you paid, then the cost of a lab report may be inconsequential. The first thing that I'd do is find a local gemologist that you feel confident in and who doesn't mind giving you an off the cuff opinion about whether a piece is worth investigating further. Many synthetics are obvious once you've seen a number of them and many natural stones have indicators that would tell someone with experience and maybe a microscope that they are looking at something that may be worth enough to spend more time with. In general if it looks too good to be true, it probably is. I mean if you think you've purchased a large, flawless ruby or alexandrite for $40, then the chances are good that you've got a synthetic. Find someone local that knows. I do this all the time for people. Most of us will, since it can lead to further work with mountings and such. Did you have a particular stone in mind ?

 

[mogok]

Well by experience when a stone is really cheap and when several possibilities are here, then assume that the stone is the possibility that is the more compatible with the price...
If you want to be able to tell more without to send the stone to a lab my best advise is to invest some time and money into books, some basic instruments or why not to spend some time studying gemology!

All the best,

 

[WinkHPD]

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On 7/24/2004 7:01:51 PM Cave Keeper wrote:

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On 7/24/2004 4:13:05 PM innerkitten wrote:

What if you want to find out if a stone that only cost you forty dollars is genuine?
:
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If it is cheap enough, I'd consider scratching something softer (also, meaning cheaper) with it to verify its hardness is at least as expected. ----------------

Bad Dragon! Back to thy cave with such heinous advice. Smack! (Sound of smoting Dragon on nose with rolled up newspaper, then snuggling down behind asbestos shield until the fireworks are over.)

Softness in itself is NOT a determinate factor in pricing. The very soft black opals (5 on the Moh's scale) may be thousands of dollars per carat, much more expensive than even the finest amethyst which is much harder. (7 on the Moh's scale.)

Beauty and rarity are more important in pricing than hardness.

The rest of your advice was definitely on target.

Wink who would never actually smote a dragon!

 

[chialea]

Isn't that conjugated "smiting" in this context?

Anyway, I think he meant "softer and cheaper". Talc is a good thing to scratch. Opals are not, period. (I also seem to remember opals having an interesting mineralogical structure such that they might be of mixed hardness anyway, but it's been a long time since I studied geology).

 

[innerkitten]

Thanks for the advice. The gem in question is a red spinel. I know they can really range in price. But it's a very nice color and so clear and I paid so little for it that it makes me wonder. The person who sold it to me claimed it was natural but I don't know. I bought it knowing that there was a possibility it might not be a natural stone but it didn't cost to much so I was willing to take the risk. Of course now I'm really curious. Michael E, your advice about finding a local person to have a quick look at it is a good one.

 

[strmrdr]

On a $40 stone if it looks good and gives you pleasure is it worth the $40?
Id just enjoy it and not worry about it.

That said ruby/sapphire/spinel I assume is synthetic and pay accordinly unless it has a cert saying otherwise from a reputable lab or is from a trusted source and from a trusted source no cert I assume its treated if its sapphire/ruby.

 

[Cave Keeper]

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On 7/25/2004 9:44:35 AM Wink wrote:

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On 7/24/2004 7:01:51 PM Cave Keeper wrote:

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On 7/24/2004 4:13:05 PM innerkitten wrote:

What if you want to find out if a stone that only cost you forty dollars is genuine?
:
----------------

If it is cheap enough, I'd consider scratching something softer (also, meaning cheaper) with it to verify its hardness is at least as expected. ----------------

:
Softness in itself is NOT a determinate factor in pricing. The very soft black opals (5 on the Moh's scale) may be thousands of dollars per carat, much more expensive than even the finest amethyst which is much harder. (7 on the Moh's scale.)
:
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Oops, there goes the $40. Sorry for the bad advice, inner kitten. Back to the Cave to test my stones.

 

[WinkHPD]

Ahh, if I were only a cave keeper. Then people would give me a cave full of stones in tribute and I could just go test them whenever I wanted!

Wink