My tray of Sheaffer flat-end pens in Jade Celluloid. Finding green pens is not difficult. Finding them with clean color is a heftier challenge. These fairly well pop.
There is a great deal to consider in this tray.
The green pen 4th from left is a very pale green. The color wholly is even, cap and barrel. The pen is pre New Old STock. No nib, no lever, no signs of use, apparently never made into whole pen, no sac. Some have claimed this was a different shade from get go. It is quite possible though that some jade pens, maybe early jade pens, had intrinsic instability, blanching from light or spontaneously (no protected areas, even where barrel covered by cap). Pens that went pale also discolored by typical fashion, so barrels can be ambered, etc.
There is a cutaway demo in the middle.
The OS pens and most to right of the are late product, 1930's, off catalogue, without lever pins, having later lever ring. Things mix up a bit for the last few items. note the Quill pen, (black tail)
There is a perfect Transitional or Half Balance pen near right, a flat-end Univer that is a rebadged/sub-brand Sheaffer and a round-ended (but not really streamlined) sub-brand/rebadged Craig (Craig Sheaffer was Walter's son).
I don't collect flat-end Sheaffers in completist fashion, so I don't buy weak jade for my collection, but when a crisp-color pen turns up, if a duplicate it goes to the website, if not I add it to the collection
regards
david