Canary diamonds

Jewelry Discussion
1 
    I just wanted to 'review' one point you made about canary
diamonds in the highlighted passage above. Not all Z+ yellow
diamonds should be termed canary diamonds. Fancy, yes, but canary,
no.

And difficult to agree upon as to which levels of tone and
saturation qualify a diamond to be called “canary.” One person’s
“canary” is another person’s “Fancy Intense” or “Fancy Vivid.” To me
(and most gemologists) the word “canary” is too vague, and leaves
too much to personal impression. What I envision as “canary” may
turn up to be “Fancy Light” when it arrives. I could never order a
fancy colored diamond by a romantic description like “canary”
“champagne” “cognac” etc., sight-unseen. Give me a more documented
term.

James in SoFl

2 
   And difficult to agree upon as to which levels of tone and
saturation qualify a diamond to be called "canary." One person's
"canary" is another person's "Fancy Intense" or "Fancy Vivid." To
me (and most gemologists) the word "canary" is too vague, and
leaves too much to personal impression. What I envision as "canary"
may turn up to be "Fancy Light" when it arrives. I could never
order a fancy colored diamond by a romantic description like
"canary" "champagne" "cognac" etc., sight-unseen. Give me a more
documented term.

James,

When going by colour alone you are correct with your observations
above. However at a gemological level, as I have mentioned before,
‘TRUE canary diamonds’ are considered to be a specific Type (Type Ib)
and even a fancy intense or vivid of another type (Type Ia, the most
common type of diamond as 95+ % of diamonds are of this main type
that may be subdivided into Types IaA, IaB or IaA/B) is not
‘strictly’ classified as a ‘true canary’.

The UV-vis and FTIR data of all these types vary from one another,
so allowing for their differentiation. When you then consider that
only 5% or less of the world’s diamonds consist of either Type Ib,
Type IIa and Type IIb diamonds it just shows how rare these latter
three types (including true canary diamonds) are in the context of
things. Who said diamonds were boring? :wink:

Regards - Nick