This is a great jar I obtained recently from Ebay.  The seller had it mixed in with three very ordinary aqua wax sealers and the picture in Ebay showed only those three jars.  When you looked into the info, this jar was shown against a black background where it was difficult to make out the color and listed last in his description as a "cobalt corker".  I have no idea where the other three jars are, but this one is beautiful.  It's got a great amber pontil on the bottom, is very whittled and the color is much deeper than it appeared in Ebay.

This type of jar with the rolled lip is very early though fairly common in aqua (albeit without a pontil).  We call them corkers and that's probably the way most of them were sealed, however, if a Willoughby stopple fit in, I'm sure they were used sometimes and this one fits in perfectly in this jar (though it didn't come with it).  So I'm being perhaps a tad less than original to display it with a Willoughby, but it looks so good in there and it's such a small offense, that I'm leaving it just as is.