Biggest black star sapphire

[colorchange]

Hi everybody,

I see very often some black sapphires over 10 Ct and up to 50 Ct but rarely above (indeed, I have seen only once a very big star sapphire and bought it...).
Anybody has an idea of the rarity of, say, 200 Ct and more or even 500 Ct and more black star sapphire, I know some are produced in India, and have seen some very big star rubies "porcelain quality" produced there (up to almost 1000 Ct once cut in a regular cab) but don't know what has been produced in black star sapphire.

Another related question : every star ruby I have seen from India have some orange stains in fractures, do anybody know what it is ?

Any information welcomed.

Thanks

 

[Richard M.]

Date: 6/23/2006 10:16:59 AM
Author:colorchange


Anybody has an idea of the rarity of, say, 200 Ct and more or even 500 Ct and more black star sapphire, I know some are produced in India, and have seen some very big star rubies ''porcelain quality'' produced there (up to almost 1000 Ct once cut in a regular cab) but don''t know what has been produced in black star sapphire.

Hi CC,

Black star corundum is pretty abundant and I don''t know of anyone keeping records of size. I know of one specimen mined in North Carolina, USA that weighed over 300 pounds avoirdupois. It wasn''t all gem quality of course but it was a single crystal.

The Mysore star ''rubies'' can get pretty big and considering the density the carats add up quickly. I can''t quite visualize a 1000 carat/200 gram corundum cab but it probably wouldn''t be enormous, especially if cut in the standard high dome with lots of Asian-style ''belly.'' I used to have some rough Mysore crystals that would probably yield cabs in the 500 carat range.

Interesting topic; I''ll look for more info.

Richard M.

 

[colorchange]

Thanks for your answer Richard,

Indeed I had a track of a 2400 Ct star ruby from India.
I personnaly have a (not very good : purplish red, heavy cracks, some small black spots) 880 Ct star ruby and a 440 Ct (rather fine quality) black star sapphire.
The star ruby is 54 x 47 x 28 mm, the black star sapphire is exactly the size of the Lincoln medaillon on a $5 bill : 44 x 37 x 22.
Both make good paperweigh

, but I prefer the black by far...