Red stone question?

[coolguynamek]

Can any body let me know ?

A red stone (ruby / sapphire) of around say 30-40 carat even if it is synthetic / natural is its hardness is 9?

Still if even it is heated or synthetic does it has any value?

No stone can bite this red stone and the red stone scratches all the stones?

can we say its a natural ruby...

coz i have seen these stones with the collectors only ....

 

[valeria101]

I bet it is some sort of synthetic... simply because of it's size. Lack of any internal characteristics would only confirm this. Even a garnet would be quite unusual and valuable in this size; I don't want to think of "ruby" in the context.

As for what kind of synthetic - it is harder to say, but many are harder than and scratch glass. It is definitely not usual to find synthetic corundum cut this big - even less than huge faceted CZ: they are playful pieces, but totally incredible after all.

What does it look like: transparent? faceted? mounted or not?

 

[coolguynamek]

They are oval shaped. looks like brilliant cut also. If i was having the pic then i would have posted here .... But still synthetic stones doesnt scratch any stones such as sapphires ? is it true?

 

[mogok]

Well Ruby is ruby wether it is synthetic or natural... The word "synthetic" before the word "ruby" for example just means that the stone was made by men. It has so all the physical and optical properties of the natural ruby but not the same value (as it is not as rare) and not the same inclusions (as it has grown differently).

Now it is true that if you study the corundum familly very closely that blue sapphire is slightly harder than ruby, especially if it is a star sapphire... Even rubies show a very slight different hardness depending of the trace elements they host. But the difference in hardness is not that important.

So you cannot say that if a red stone scratches all the other stones that it is a natural ruby. You can be pretty sure that it is a ruby but hardness is not a diagnostic test to determine weather a ruby is natural or synthetic.

All the best,

 

[Cave Keeper]

Then it could be a either a red diamond, a red Russian diamond or a red Moissanite.

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On 9/16/2004 12:21:52 PM coolguynamek wrote:

:
No stone can bite this red stone and the red stone scratches all the stones?
:
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[yowahking]

Back up Cave Keeper, now that you got her all excited, no such red diamond, Russian Red, or Moissanite (gag)is available in 30-40ct size. And for Anna, simmulated ruby is abvailable cheap, but synthetic ruby such as Chatham, Ramora, etc. is not cheap and also not available in 40 ct size. Simmulated Ruby matches color but is not part of the same hardness, specific gravity, chemical elements as natural ruby. Synthetic or lab grown ruby does not spend the money it would take to create a duplicate of a gem that is so rare. The market is for small to 10ct models mostly. Mr. Chatham would love to grow 40 ct stones if he could do it cheaply.

 

[Richard M.]

Scott,

It seems to me you're overlooking the Verneuil flame-fusion synthetic corundums. They're cheap, occur in sizes much larger than 50 carats (see the image from the Richard Hughes site!) and are definitely "real" ruby and sapphire. Even the flux synthetics like Chatham and Ramaura and the hydrothermals from Russia are not absolutely identical chemically to natural ruby (which itself has minor chemical variations from locality to locality).

There are also plenty of low-grade natural rubies like the huge red asteriated crystals from Mysore, India and other locations. Some are suitable only for carving or fishtank gravel. I just visited a website where you can buy big chunks for $25/lb. The only thing that determines value in any gem is quality, quality, quality -- then size and rarity.

Cheers,

Richard M.

 

[Richard M.]

I forgot to include the name of the big boule image -- "Rubylope," although it's probably pink sapphire. It's just a gag to show the size some boules can be grown to.

 

[yowahking]

Yes, I did pass over that variety. However if the example was 50 ct faceted bright material, it would not be the fish tank stuff from India. Even the flame fusion bouls are rare to cut 50ct bright ovals. There is just not much market. While I have a couple bouls in my safe somewhere, we use them once in a blue moon for estate repairs when grandpa's ring is beig passed on and the stone is damaged. Thanks for pointing out my error, I still doubt whether it will be Ruby or any variety. I guess simulant. Happy to fess up if I am proven wrong.

 

[Cave Keeper]

A certified gemologist kindly sold me a large emerald-cut synthetic ruby about 15 years ago to satisfy my curiosity about rubies. At that time, I only wanted to know what top-grade rubies should look like. It was about thumb-size (about 3 cm. long)and weighed about 8 gms. Should have asked him whether it was Pigeon Blood red, but then at that time I only knew the word 'pure red' for 'red'. So there.

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On 9/26/2004 8:29:16 PM yowahking wrote:

:
synthetic ruby such as Chatham, Ramora, etc. is not cheap and also not available in 40 ct size.
:
Synthetic or lab grown ruby does not spend the money it would take to create a duplicate of a gem that is so rare. The market is for small to 10ct models mostly. Mr. Chatham would love to grow 40 ct stones if he could do it cheaply. ----------------

 

[yowahking]

Not enough people carve up pigeons to know what their blood looks like anyway. Just like cornflower blue sapphires. Since I am a hick that grew up in corn country, I enjoy asking when someone has seen a cornflower when tossing out the term, same goes for pigeons blood. Most likely you have either a simmulant or the flame fussion type like Richard pointed out. Check prices on large gemmy Chathams sometime....wow. Big bucks for stuff grown in a lab. I got to hold a 7 million dollar natural unheated ruby in HK last week. That was fun since I will most likely not ever own one.

 

[Richard M.]

Scott,

The original post said "30-40 carats." I know a supplier who provides split ruby boules up to 250 carats that would yield cut stones of that weight, especially in oval shape. A big split boule would practically be an oval preform -- there would be very minor cutting loss with the table oriented parallel with the flat part.

Ruby laser rod is often faceted by hobbyists and some mighty big stones of that material are kicking around. Also, sapphire made by the Czochralski pulling method yields roughs up to 500 carats. The magenta color is red on the c-axis and yields very large cut stones. There's also plenty of red CZ out there, hardness 8.5.

From only the description given it's very hard to guess what the stone might be other than the suggestions made already. I missed the reference to brilliant cut and agree it wouldn't be the lower grade opaque Indian or African corundum although I've seen them faceted.

Richard M.

 

[coolguynamek]

Most of the stones such as the red,blues,etc.. are mostly found in India . Even most of the diamonds that are listed in famousdiamonds websites are from India. isn't it right?

coolguy