I am very interested in English jet and I was watching on Ebay .
I saw in US Ebay this :
this authentic Victorian Mourning period Whitby Jet necklace measures 40" from end-to-end and is composed of all faceted Whitby Jet beads. The cord seems to be very old, perhaps original to the beads, and is offered just as found; hand-knotted. These have tested positive for Whitby via the pottery test and are guaranteed as such!