Just adding for information -
There is a pink bell with a gilded handle online. It looks to be solid colour uncased (similar pink colour to the jug as it looks on the black background in reflected light).
It appears currently top left on this pinterest link (sorry I can't track the original source):https://www.pinterest.com/pin/307018899574621326/
The handle is very similar to this onehttps://new.liveauctioneers.com/item/20419660_tischglocke
which is described as Russian.
There is a Russian bowl in the Hermitage that is the same solid pink (uncased) glass.
I do not think the shape of the creamer is a Russian shape and the creamer is cased, unlike the bowl on stand in the Hermitage and the bell which is like the one I've linked to above.
I am still sure of my attribution as Buquoy so far.
I believe the one in the Corning and the three others I've found, are different to those described as Agate glass or Agatin glass or 'stone glass' from Buquoy.
The 'Agatin' glass or stone glass appear to be solid coloured (whether created in layers of different colours I don't know).
For example Dr Fischer describes one here:https://new.liveauctioneers.com/item/9713661_24-an-agate-stone-glass-goblet-buquoysche-htten-geo'An agate stone glass goblet Buquoy'sche Hütten, Georgethal or Silberberg, circa 1835 Purple, marbled, opalescent, cut and engraved glass with gold staffage. Friezes with acanthus, insects and blossom branches. 15.2 cm high This originally French aristocratic family came to Bohemia shortly before 1620. Stone glass was a glass of special strength, glance and impermeable to light and resembled more a precious stone than glass. The decoration of this type of glass was increased by gilding and cutting.'
The five I've linked to including the Corning piece are cased in transparent glass:
Corning purple goblet, beige goblet, blue goblet, grey greeny flakon, dark pink purple flakon (can't find link).
There do no appear to be any more around that I can find,that are made in this way with an opalescent opaline interior and then transparent exterior.