It is a "hollow blown Fly weight", according to information in the Paperweight Collectors Circle Newsletters, editions 84 & 86 of 2004.
Two of these weights, one clear and one green, were shown with a request for information about them. A response was received from a PCC member, who was assisting Broadfield House Glass Museum in cataloging a family collection of glass items. One of these weights in clear glass was in the collection of the H G Richardson family.
There were several members of the Richardson family who owned glassworks in Stourbridge, England, from the mid 1900s to circa 1930s. Given the family provenance, it may be that these Fly weights were made at the H G Richardson company. But exactly when is hard to say.
It is also not easy (for me, at least!) to find precise data on when that company started and finished. So, "late 19th century to first quarter of the 20th century", as stated in the PCC Newsletter, may be the best we can do.