Can anyone please explain the meaning of a tiny, circular stamp in the shank briar of a Castello Collection Fiammata. I can find no reference to such a mark anywhere online or in pipe discussion forums. It's neither the usual castle or a k or g stamp - in fact the pipe has none of those at all. The mark appears just above and to the left of the C in the name, CASTELLO, and is just slightly bigger than the letter. It is perfectly round with four short etched lines radiating out of the bottom. At first glance it looks like a spider with four short legs peeping out of its side. Even viewing it through a magnifying glass is insufficient to clarify the wedge-shaped marking inside the circle - perhaps best described as that of a tiny hot-air balloon. Aside from this mark, there are the three words identifying make and model (CASTELLO COLLECTION and above those, FIAMMATA). Beneath these is a punched signature of Carlo Scotti. Elsewhere on the shank are the usual oval-circled "Carlo Scotti" and "Made in Cantu Italy" markings. As indicated by the make and model, it is a beautifully-crafted straight-grain smooth briar pipe of unusual design - almost a freehand, with plateau rim - with a flat bottom allowing it to stand and bent, lucite stem, with the trademark white bar facing up.