It depends on your definition of "white" (or "yellow"). Since by and large yellow in diamonds is caused by nitrogen, one could insist that only type II diamonds are "white" (if they are colourless and not blue, pink, red or brown).

The GIA scale goes

D-F colourless
G-J near colourless
K-M faint yellow
N-R very light yellow
S-Z light yellow

and then Fancy Something, where it's not just saturation but also tone that determines whether there is more or less "yellow" (e.g. Fancy Dark has less yellow than Fancy Intense, but with a darker tone, however Fancy Light can be more saturated yellow than Fancy, but with a lighter tone - in other words, it's a bit of a mess).

Add in that the perception of colour is highly dependent on the optics (size, cut and observation angle), fluorescence, the environment (lighting, setting, surroundings) and is anyway quite an individual thing, and a diamond can begin to look yellow pretty much anywhere south of Golconda.

So, is "M" yellow? Well, as you say, M is M. It can look yellow in a stone cut and set to maximise that aspect (say a 4.00 ct radiant set in 22k gold), and it can look white in another stone (say a 0.50 ct round set in platinum) when observed through the table.

Another part of the answer is how does GIA grade for colour. The answer is that for diamonds that have no hues other than grey, brown or yellow, they will use observation through the side up to Y-Z; if the diamond has more body colour than a Y-Z, then it will be turned face up and graded through the table in one of the Fancy colour grades. Other colours go straight to a face up grading, and get classed using the adjective scale (Faint x --> Deep or Vivid x). BTW, GIA will grade some diamonds as Fancy White - which is not at all the same as colourless; they look milky.

I like to call "brown" diamonds  "champagne" and faint yellow diamonds "ivory"...more appealing this way!

Truth is, I only started to appreciate the "ivory" colored diamonds since I discovered DBL's website.  So, kudos to David for making those "other than" colorless diamond shades so appealing!  

There are all sorts of scales that are used by other labs or were used in the past, and "Top Light Brown" is a nicer (if less precise and no longer used) expression than N, Light Brown. Meaning they have an N level of saturation, and the hue is brown. Top Light Brown means the same thing - more or less - but using a different scale. This Wikipedia article has a pretty clear comparison of terms and diamond grading scales: http://en.wikipedia....g/wiki/Diamond_color - and again in the relevant scale you see another euphemism for "yellow" which is "cape" (diamonds from the Cape as in South Africa's Cape Town region are predominantly yellow, and much more so than historically diamonds from India or Brazil were).

Not really. True colour is a continuum (certainly as far as the human eye can see) on which someone has imposed steps with a grading scale. There is a J which is almost a K and a J which is almost an I. The D-Z scale used at GIA is the same throughout, independent of the hue. When it comes to colours other than yellow, brown or grey, different levels of saturation and tone apply to the different grades, not least because a 90% saturated yellow is quite pleasant to look at, but a 90% saturated blue is almost black - one ends up as "vivid yellow", the other as "dark blue" so that there is some match between the label and the description a non-technical person would apply.

If nothing else is specified in the GIA report it is assumed that the hue is yellow, so "Very Light Yellow" is technically correct; "M" is more precise. Which one you use, is up to you, but neither is incorrect. As a wily coyote vendor, I would use VLY if I wanted to sell the stone as a "Yellow" diamond, and "M" if I wanted to say that it is "nearly white". And some other wily marketers coyotes came up with "Champagne" and "Cognac" scales to describe light (and mid-range) browns, but they didn't really catch on, however nicer the description is.

You are most welcome!

  A wily marketer coyote...am I???  Well, you can take away my "Chocolate" but hands off my "Champagne" mister!!!   

No...but I have...and no...but I wish...and no...they're too cute! (at least from a far )   

OK, hands on, then!

OMC, what a beauty...even close up!  What shall I call her (him? )?  DD? or DC?     

Good to know, I'll make sure my dear uncle Bino is left home should I ever visit...

   

and two extra silly hounds

The third one is clearly saying: "WILL someone please scratch my tummy? PLEASE?!?!" Lovely dogs all.

oh ok, just 5 babies in all...I was a little worried for your sanity, that's all !   

   Seems to me, you have a heart of gold...   I think you should be the one laying on the couch with your belly or back being rubbed...