Rare Magnum Double Overlay

A rare magnum cobalt-blue & white double overlay cut with a large circular top facet and 10 round side facets to reveal a 5-petalled deep, velvet-blue flower with 3 green leaves rising out of a mottled, translucent pale-amber cushion. (appears black!)
According to Dave Moir who worked at Strathearn, most weights of this type were made by himself and Herbert Dreier in the mid to late 1970s. Slightly concave polished base.
(See page 87 in John Simmonds' book “Paperweights from Great Britain 1930-2000" for a similar blue flower & overlay).