In all the years I've collected flips, I have only seen two of these and paid dearly for both of them. And it is only because I have two that I'm willing to offer one for sale.
The bowl is 4 1/2" in diameter by 2 7/8" high, not including the lovely rounded knob. It is completely unmarked. There is no manufacturer's mark on the lid or impressed into the bowl.
The bowl itself is in excellent condition and has no chips or cracks. There are several areas that feel slightly rough on the outside of the foot. It is possible to see that two of these are mold marks and under strong light, three look like tiny nicks – but too small to photograph.
There is a band of paler marbling that goes around about two-thirds of the lower part of the bowl, and we believe this is typical of Jadeite. You can see it in the additional photos, and it appears more pronounced in the photo than it really is.
Like true Jadeite, the color goes all the way through the glass.
The metal lid is in good overall condition as the hinges are tight and intact. However, the chrome on the top of the lid has heavy damage and has been partially worn away. Underneath, the chrome is still mostly shiny but has myriad scratches from cleaning. The lid cannot be removed, but it will spin freely around the bowl. In addition, the metal on the rim has some dents in it between the knob and the hole for a spoon.
I would estimate that this piece dates to the 1930s.