good article I found on researching diamonds

[pyramid]

http://www.giionline.com/articles-2.htm

 

[pyramid]

In the above article it states that SI1 and SI2 are not subdivided anymore, is this true with GIA or only the lab in India?

QUOTED FROM ARTICLE ABOVE:
"SI1 and SI2 diamonds

Lately this grade is not sub-divided any more, that is, the group has been condensed and inclusions which up to some time ago would be classified as SI1 and SI2, are now graded as I1.

The SI2 grade has inclusions that can be easily seen with 10x loupe in the table but not visible with naked eye. It may have some definite external features.

With increasing size and number of inclusions in the I grades two further definite criteria are added. : recognition with the naked eye, solely through the crown in natural day light and the influence of inclusions on the brilliance effect".

 

[Garry H (Cut Nut)]

Interesting Pyramid - I have asked their cheif instructor.
I made a presentation there for GII last month.

 

[strmrdr]

http://www.giionline.com/articles-6.htm