African Rubies

[JTM933]

I have some rubies that are from 2 ct. to 7 ct. I would like to know if anyone can help me out getting a ball park range of the quality of these rubies. I know I do not have the best of pictures right now but I will add some later.

Thank you,
John

 

[chrono]

Have they been heated?

How about a few table view?

 

[Pandora II]

Can you take some pictures without a yellow background?

The yellow will skew the pictures and make the rubies look much redder than they may really be.

It's worth watching out for that if anyone is thinking of buying a ruby in the future. It's a trick some unscrupulous dealers using - showing them to you on a yellow cloth or brass plate. I had a couple of dealers do that to me when I was buying some stones for the company I worked for - I told them not to bother showing me anything else, and not to bother coming back again.

 

[strmrdr]

Date: 2/18/2008 1:11:58 PM
Author: Pandora II
Can you take some pictures without a yellow background?

The yellow will skew the pictures and make the rubies look much redder than they may really be.

It''s worth watching out for that if anyone is thinking of buying a ruby in the future. It''s a trick some unscrupulous dealers using - showing them to you on a yellow cloth or brass plate. I had a couple of dealers do that to me when I was buying some stones for the company I worked for - I told them not to bother showing me anything else, and not to bother coming back again.

yep and works well at hiding the brown undertone of African Rubies.
African Rubies are some of the easiest too spot.

 

[DiamondExpert]

The simple fact is that colored gemstones and diamonds are frequently/almost always shown under conditions which favor the merchandise, whether it''s colored paper, lighting, general conditions...but this is done at all levels of the trade, and is not done, at least on most cases, as an attempt to screw the buyer...it is just the way business is done, and the smart buyer will always take that into consideration when making a purchase...trust (until you have reason not to), but verify...but don''t (possibly) short change yourself by not dealing (with the situation).

 

[Harriet]

Do you mind if they''ve been flux healed?

 

[strmrdr]

Date: 2/18/2008 7:31:42 PM
Author: Harriet
Do you mind if they''ve been flux healed?

If they are truly African rubies they aren''t likely flux healed.
High heat increases the brown tone so isn''t used much.

 

[Richard M.]

Date: 2/18/2008 10:33:16 PM
Author: strmrdr

Date: 2/18/2008 7:31:42 PM

Author: Harriet

Do you mind if they''ve been flux healed?

If they are truly African rubies they aren''t likely flux healed.

High heat increases the brown tone so isn''t used much.

Africa produces rubies from several locations. The most abundant African rubies on the current market are from Madagascar. Both flux and lead glass filling is almost expected in Madagascar goods -- I saw piles of them in Tucson last week at low prices. Most rubies (other than those intended to be glass filled) are heated to reduce or eliminate blue and brown overcasted colors.

Rubies with a blue or purplish overcast are heated in an oxidizing atmosphere which helps drive off the undesirable hue. Those with brown overcast are heated in a reducing atmosphere to accomplish the same goal. It''s all very complex and the origin of the stones plus the colors present determine the temperature, type of atmosphere and length of treatment. A lot of heat treatment is simply trial-and-error. As an example one heater cites translucent to opaque dark red rubies from Tanzania. They were heated in an oxidizing atmosphere at 1800C for 4 hours. The color after heating was purplish-bluish with white streaks. Whoops!

 

[strmrdr]

Date: 2/19/2008 1:02:58 AM
Author: Richard M.


Africa produces rubies from several locations. The most abundant African rubies on the current market are from Madagascar. Both flux and lead glass filling is almost expected in Madagascar goods -- I saw piles of them in Tucson last week at low prices. Most rubies (other than those intended to be glass filled) are heated to reduce or eliminate blue and brown overcasted colors.

Rubies with a blue or purplish overcast are heated in an oxidizing atmosphere which helps drive off the undesirable hue. Those with brown overcast are heated in a reducing atmosphere to accomplish the same goal. It''s all very complex and the origin of the stones plus the colors present determine the temperature, type of atmosphere and length of treatment. A lot of heat treatment is simply trial-and-error. As an example one heater cites translucent to opaque dark red rubies from Tanzania. They were heated in an oxidizing atmosphere at 1800C for 4 hours. The color after heating was purplish-bluish with white streaks. Whoops!

looks like my info may be out of date over which is being imported.. thanks.

But my source does say that brown tone will be heated at low heat not high as too not make the brown tone worse.

 

[Richard M.]

Date: 2/19/2008 2:01:03 AM
Author: strmrdr

looks like my info may be out of date over which is being imported.. thanks.


But my source does say that brown tone will be heated at low heat not high as too not make the brown tone worse.

 

[JTM933]

Huh, sucks about the yellow paper thing I would not even think about that! I guess it is good that whenever I select an individual gem I take it out and get close with it, tricky buggers. How are some ways to tell if these have been heat treated or glass inundated?

 

[beaujolais]

Do you really think so? Please explain. I''m intrigued as to why you don''t like them.

I, myself, love quotes. There are alot of great minds out there with great ideas.

 

[JTM933]

Haha, yeah I know, I am in the Army and it is kind of a joke we have; everything when you are in the army is either "for the weak" or "a crutch". Such as "food is a crutch", "painkillers are for the weak" and so on. So there it is!

 

[Richard M.]

Date: 2/19/2008 2:01:03 AM
Author: strmrdr

Date: 2/19/2008 1:02:58 AM

looks like my info may be out of date over which is being imported.. thanks.


But my source does say that brown tone will be heated at low heat not high as too not make the brown tone worse.

Didn''t proof my post to you previously. Maybe the treatment you''ve been told about has something to do with the source of the rubies. Thai rubies have lots of iron, for instance, and are always heat-treated to diminish the brown overcast. I don''t know what temp is used but the same treatment would probably be given to any high-iron stones from whatever source. There''s simply no "one size fits all" solution to heat-treating.

 

[Richard M.]

Date: 2/19/2008 10:43:10 AM
Author: JTM933
How are some ways to tell if these have been heat treated or glass inundated?

The best way is to have them examined by a qualified gemologist. Answering your questions requires equipment you''re not likely to own, considerable specialized knowledge and experience.

Richard M.

 

[JTM933]

What is the usual price range per carat for these heat treated African rubies?