Is it possible these were, or could be replaced by, rose cut
pyrope garnets. There is quite a bit of old Bohemian garnet work
around and it might be rather easy to salvage a pair of 2.5mm
stones. The real old pyrope has a very nice deep red color.
Please do not break up Victorian Pyrope Garnet jewelry to salvage
several inexpensive replacement stones.
This style of Victorian jewelry is very collectable and bring fairly
good prices in fine condition.
Contact a cutter on Orchid or your local gem and mineral club to
find someone to cut the stones you need.